Ìyá as a status and a philosophical category, the world's highest twinning rate and what the Yoruba built on it, what infertility actually costs a woman, àbíkú and the medical evidence behind it, and the ìyá abiye who delivered the children.
Bearing children was the central determinant of a Yoruba woman's social position. That is a plain statement of what the ethnographic record shows, and it sits uncomfortably beside every account of Yoruba women's autonomy, including the ones in this section, without cancelling them. A woman could be a trader with her own capital, a titled chief, a priestess before whom a king knelt, and still find that the question of whether she had borne children governed her standing in the compound she lived in.
This file treats motherhood as a status, as a philosophical category, and as a physical event, and it sets out what the evidence documents rather than what the tradition says about itself in its most flattering register. The twins material is treated as art and religion in Ìbejì and Ìbejì figures; here it is treated demographically and as an obligation falling on mothers.
Ìyá is conventionally translated "mother", and the translation is inadequate in a way that has been argued about seriously.
Oyèrónkẹ́ Oyěwùmí's What Gender is Motherhood? Changing Yorùbá Ideals of Power, Procreation, and Identity in the Age of Modernity (Palgrave Macmillan, 2016) extends her earlier argument into this domain and proposes matripotency as the name for what ìyá denotes: the spiritual and material authority of ìyá deriving from the procreative role, with the relationship between an ìyá and her own birth children as its most potent expression . Her structural point is that the matripotent ethos is bound to the seniority system, since an ìyá is by definition senior to her children and every human being has one, so that no one is senior to their ìyá . Her objection to the English translation is that "mother" fails to carry the core meaning and distorts it .
Two things about this argument are worth separating.
The observation about seniority is well founded and is visible everywhere in the material. Ìyá is used as a term of address and respect far beyond biological motherhood: the Ìyálóde, the Ìyálọ́jà, the Ìyálòrìṣà, the Ìyámọdè, àwọn ìyá wa. In each case the word marks a position of authority, not a reproductive fact. The Ìyámọdè is addressed by the Aláàfin as father; her title carries ìyá while her relational position is paternal. The morpheme travels.
The larger claim, that ìyá rather than "woman" is the primary category of Yoruba social organisation and that the whole apparatus of gender analysis should be replaced by it, is contested on the same grounds as Oyěwùmí's earlier work. See Gender. The reviewer's summary of What Gender is Motherhood? in the Journal of African History is worth a reader's attention as an assessment of how far the argument carries .
What is not contested is the observation underneath. Ìyá names authority, and the authority derives from the procreative relation. That is exactly why the woman who does not bear is in the position the rest of this file describes.
The Yoruba have the highest twinning rate recorded for any human population, and the anomaly is genuine rather than folkloric.
The rates are dizygotic, meaning fraternal rather than identical, and the monozygotic rate is essentially the human baseline. Nylander's work established that monozygotic twinning rates measured by sex, placentation and blood-group markers varied very little across Nigerian ethnic groups, and that the differences in overall twinning were almost entirely differences in the dizygotic rate .
The figures, from the review in the PLOS One study of Igbo-Ora:
| Population | Twins per 1,000 births |
|---|---|
| Igbo-Ora (Yoruba) | 45 |
| Yoruba, Western Nigeria (range) | 33 to 66.5 |
| Hausa, Northern Nigeria | 19.4 |
| Western Europe, 1970s | 9 to 11 |
| Japan, Hong Kong, Singapore | 5 to 6 |
Igbo-Ora, in Ọ̀yọ́ State, has the highest recorded dizygotic twinning rate in the world at about 45 per 1,000 live births . Nylander documented 45 to 50 sets per 1,000 births there in 1969 . A Yoruba woman was, on these figures, something between four and ten times as likely to bear twins as a European woman of the same period.
Nylander's dietary hypothesis, 1978. That some substance in the Yoruba diet, yams being the candidate, produces high serum concentrations of follicle-stimulating hormone and so raises the rate of double ovulation . This is the hypothesis that entered popular writing and it is very widely repeated as settled. It is not settled.
The community's own explanations. The PLOS One study asked and found three: that God created the people of Igbo-Ora specially to bear twins; heredity, described as a bond or cord of twins in the population; and diet, with ìlásà, okra leaves, ranked highest, taken with àmàlà, along with the local water . The finding the authors highlight is that yam, the substance the scientific hypothesis had focused on for forty years, did not rank highly in the community's own account, which they suggest is a reason to weight yam-focused research lower .
Genetics. The consistency of the elevated rate across Yoruba populations and its persistence in Yoruba-descended populations elsewhere points to a heritable component in the propensity to double ovulation. This is the mainstream reading and it does not exclude a dietary contribution.
The corpus's position: the rate is documented and extraordinary, the cause is not established, and the yam explanation is a hypothesis of 1978 that has been repeated as fact for half a century.
A society with this twinning rate had to have a settled cultural response, and the Yoruba response is one of the most elaborate in the world. It has not always been positive. The historical record includes traditions of twin infanticide in some Yoruba areas, later reversed, and the reversal itself is part of Ìbejì's origin narrative; that history is handled in Ìbejì.
What falls on the mother specifically is a set of continuing obligations. The ìyá ìbejì, the mother of twins, carries ritual duties toward the twins for life and, if one or both die, toward the ère ìbejì, the carved figures that stand for them. She feeds, washes, dresses and carries the figures. She dances and sings for the twins in public and receives gifts and cowries when she does, and the twin-mother's begging song is a recognised form. The PLOS One authors note the celebration, with beans cooked for the twins and special songs of praise, and suggest that this veneration may itself encourage twinning through community dynamics .
The point for this file is that motherhood of twins was a public office with recurring duties and a recognised entitlement to collect from the community. It was the single most visible form of ritual standing available to an ordinary woman.
This is the hardest evidence in this section and it should not be softened.
The best study is Okonofua, Harris, Odebiyi, Kane and Snow, "The Social Meaning of Infertility in Southwest Nigeria", Health Transition Review 7 (1997), based on twenty-five focus-group discussions in rural and urban parts of Ilé-Ifẹ̀ . Their prevalence review reports that infertility rates in Nigeria may be as high as 30 per cent, that population-based data suggest up to 30 per cent of couples in some parts of Nigeria may have proven infertility, and that a community-based study of women of reproductive age in Ilé-Ifẹ̀ found nearly 20 per cent infertile . Infertility cases constitute between 60 and 70 per cent of consultations in tertiary health institutions .
Note that these are largely rates of secondary infertility, driven substantially by untreated reproductive tract infection, and are not a statement about an inherent condition. Note also that male factors are well documented: in one group of couples, eight of seventeen men whose wives had been reported infertile, 47 per cent, had severe semen abnormalities capable of causing it .
The study's findings are worth setting out at length because they are specific and because they come from Nigerian and Nigeria-based researchers asking the community directly.
Women receive the blame. The authors record that women are most often blamed and that there are many who believe a man cannot be infertile, fertility and potency being thought synonymous .
The common consequence is expulsion. "A common consequence of a couple's infertility is the expulsion of the woman from the husband's house, with or without divorce," and the phrase respondents most commonly used was that the husband would "send her packing" The authors' conclusion from this is blunt: having children is clearly more important than loyalty to a spouse .
The exclusions are then systematic. The woman becomes an outcast and is excluded from inheriting property, from decision-making in the family, and from financial or social security . Her ability to make decisions in the family and to inherit her husband's property are "almost exclusively dependent upon fertility", and she might be allowed such privileges only if she behaved well and was liked by her husband's family; inheritance required a written will specifically designating property for her . If she is not liked she is evicted from the compound when the husband dies .
Social avoidance follows. People avoid women known to be infertile and mothers tell their children to avoid them, either fearing that the woman might harm the children out of bitterness or that she would not know how to look after them .
And the àjẹ́ accusation attaches directly. A significant number of the focus groups reported strong beliefs that some infertile women were witches who had borne children in another world and taken a secret vow never to bear children on earth, a belief the authors say justifies ostracising and expelling them; subsequent misfortunes to the woman or the family are then attributed to her infertility or her witchcraft . This is the same mechanism described in Àjẹ́ and Our Mothers, operating on the woman who has not borne rather than on the woman who has accumulated.
Remarriage is constrained. A divorced infertile woman can remarry, but if she stays in the area she may struggle to find a husband unless he is older and needs a carer or is already polygynous with children, and the former husband's family may warn other men away, so that moving far away is considered best .
Finally, the authors record exploitation in the course of treatment, including a physician's account of a herbalist who used sexual intercourse as part of the treatment of a woman whose husband was azoospermic, and their explanation that a woman might be desperate enough and under enough family pressure to submit to such abuse .
The authors' summary of how a woman's fate is determined is important because it resists a simple rule: the consequences do not follow strict guidelines but depend on the objective circumstances of her infertility and her position in household, family and community, and on a subjective assessment of "how good she is", her past conduct and her treatment of in-laws and of the children of other wives .
Three treatment outlets are used, often in combination: churches and spiritualists, traditional healers, and hospitals . Orthodox treatment is used less, for two stated reasons that are worth noting: perceptions about the causes of infertility, and lack of confidentiality at treatment centres . Confidentiality is not a minor point in a setting where the social consequences above follow from being known to be infertile.
Ifá consultation, sacrifice prescribed by a diviner, and appeal to particular òrìṣà are the older recourses. Ọ̀ṣun is the one most associated with granting children, and the Ọ̀ṣun-Òṣogbo festival's central petition is for children; see Ọ̀ṣun. The Gẹ̀lẹ̀dẹ́ origin verse is itself a fertility narrative, in which Yemọja or Ìyá Nlá is childless, consults Ifá, is told to dance with wooden images on her head and metal anklets on her feet, and conceives; see Gẹ̀lẹ̀dẹ́. The institution most celebrated as evidence of Yoruba respect for women's power originates, in its own account, in a woman's infertility.
Àbíkú names a child understood to be born repeatedly to the same mother and to die repeatedly in infancy, having agreed with its spirit companions to return. From à-bí-kú, one who is born to die.
The response is a set of practices aimed at making the child stay. The most visible is naming. Protective names include Málọmọ, do not go again; Dúrójayé, stay and enjoy life; Kòkúmọ́, does not die again; Bánjókòó, sit down with me; Ìgbẹ́kọ̀yí, the bush rejected this one; Kòsókó, there is no hoe to dig a grave . Some of these are names of insult or of worthlessness, given on the reasoning that a child who is not valued will not be worth taking back. Ritual responses include scarification and marking of the body, on the reasoning that a returning child bearing the marks will be recognised and the cycle exposed, and burial practices intended to prevent return .
There is a demonstrated relationship between the àbíkú complex and sickle cell disease, and it should be stated carefully because it is easy to state badly.
The key study is Esther Nzewi's, published in Social Science & Medicine in 2001, of the Igbo equivalent ogbanje. She examined the culturally defined symptoms of 100 children classified as malevolent ogbanje and investigated their family history and child mortality experience. Haemoglobin analysis showed that 70 of the 100 had sickle cell disease, 68 families had death-related names, and there was concordance between the cultural description of malevolent ogbanje and the symptoms manifested in sickle cell patients .
Nigeria carries the world's highest sickle cell burden, with roughly a quarter of the population carrying the trait and on the order of 150,000 affected infants born annually . In a population with that carrier frequency, two carrier parents have a one-in-four chance per pregnancy of an affected child, and untreated sickle cell disease in that era killed in early childhood. A couple would therefore see repeated infant deaths, clustered in one family, with a recognisable and recurring set of symptoms, and with normal children in between. That is precisely the pattern àbíkú describes.
Three cautions.
The correspondence is strong but not total. Sickle cell disease does not account for every case, and the higher general infant mortality of the period, from malaria, malnutrition and infectious disease, produced repeated infant deaths in many families without any single underlying genetic cause.
Saying that àbíkú "is" sickle cell disease is a category error. Àbíkú is an explanatory framework for a pattern of experience. Sickle cell disease is one of the things producing that pattern. The framework does other work as well: it gives grieving parents an account, a set of actions and a vocabulary, and it has generated a substantial literature, from J.P. Clark and Wọlé Ṣóyínká's poems to Ben Okri's The Famished Road.
And the practical consequence for mothers was, and to a degree remains, that the framework directs response toward naming and ritual rather than toward haemoglobin screening. Nigerian public health messaging on premarital genotype testing addresses exactly this.
The Yoruba traditional birth attendant is the agbẹ̀bí, deliverer of babies, or ìyá abiye, and she was until the twentieth century the person who attended virtually every Yoruba birth.
The training was long and formal. Olorunnibe and Msindo document an apprenticeship of seven to ten years, beginning with observation and progressing to practical involvement in preparing herbs and learning diagnosis, and describe the ìyá abiye as highly respected practitioners embedded in their communities providing antenatal, delivery and postnatal care, using herbal preparations, àgbo, and holding spiritual significance in childbirth practice . Others describe the same training as passed through generations with high standing for those who completed it .
The colonial encounter with this institution followed a documented arc and it is the most useful thing in the literature for understanding what happened to women's specialist knowledge under colonial rule.
Missionaries and colonial officials initially condemned traditional midwifery as unsanitary and unscientific and sought its abolition. By the 1940s, facing inadequate rural healthcare coverage, continued community reliance on the ìyá abiye, and limited colonial resources, the authorities reversed course, and the 1946 Midwives Ordinance brought traditional birth attendants formally into the maternal healthcare system, producing what Olorunnibe and Msindo call a medical pluralist society . Their characterisation of the shift is that it was pragmatic accommodation rather than ideological acceptance: administrators recognised they could not eliminate the practice, so they registered, trained and supervised its practitioners in order to promote hygiene, emergency referral and the adoption of Western medicine, using the ìyá abiye's community trust and existing networks .
The implementation produced tensions the authors document: trained African midwives saw the ìyá abiye as professional competition, some traditional practitioners resisted hospital protocols, and there were conflicts over intervention in birth .
The arrangement persists. Traditional birth attendants continue to deliver a substantial share of births in the southwest, and the modern policy approach continues the 1946 logic of integration and referral rather than replacement; the Ondó State Agbẹ̀bíyè scheme, under which attendants refer pregnant women to government medical centres, is a contemporary instance and is associated with a reported 75 per cent reduction in maternal deaths in the state . That figure comes from reporting on the programme rather than from an independent evaluation and is presented as such.
Two propositions, both supported.
Motherhood conferred real authority, and the term for it, ìyá, became the general Yoruba word for a woman holding power of any kind, which is a striking thing for a language to do and is the strongest evidence in Oyěwùmí's later argument.
And the same system imposed on the woman who did not bear a set of consequences, documented in the 1990s and not in some remote past, that included expulsion from her home, exclusion from inheritance and decision-making, social avoidance, and accusation of witchcraft. The authority and the penalty are two faces of one arrangement, which valued women through procreation. A reader looking for a Yoruba past in which women were honoured without condition will not find it here, and a reader looking for one in which women were simply subordinated will miss the Ìyámọdè before whom a king knelt.
What aya and ọkọ actually encode, why a married woman never stops belonging to her father's lineage, the politics of co-wives, widowhood and inheritance under Yoruba customary law, and the grounds on which a woman could leave.
What àwọn ìyá wa actually names, why "witch" mistranslates it, the ambivalence built into the power, Gẹ̀lẹ̀dẹ́ as the institutional answer to it, and the Atinga witch-hunt of 1950-51 with Apter's cocoa-economy explanation.
Yoruba twins, the highest twinning rate in the world, the ere ibeji figure carved when a twin dies, and the reversal from infanticide to veneration.
The carved figures made when a Yoruba twin dies, what the family does with them, the genuinely exceptional twinning rate that produced them, and how tens of thousands of them ended up in Western collections.
The knowledge system of the onisegun, the categories of oogun, what pharmacological research has and has not confirmed about Yoruba herbal medicine, and the specialist practitioners.
Where Yoruba women stand now: near-total exclusion from elected office alongside high literacy and professional attainment, the market titles absorbed into party politics, the diaspora, and the feminist scholarship Yoruba women have produced.