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Community leader Olayide Akinyemi, a 71-year-old father of 12, said: "There is hardly a family here without a set of twins." Akinyemi was speaking as he settled a dispute between two neighbours.
He said: "My father had 10 sets, while I had three sets. But only one set, a male and a female, survived."
The town's high incidence of twins had baffled fertility experts - underscoring a more regional twin trend and an array of elaborate African rituals around them.
The rate of identical twins was pretty steady throughout the world at about 0.5% of all births, according to a 1995 study by Belgian researcher Fernand Leroy, who had worked extensively on twins.
But West Africa bucked that trend, particularly with a much higher incidence of fraternal, or non-identical twins than in Europe or Japan. That was especially true, said experts, amongst Nigeria's Yoruba community, which was largely concentrated in the southwestern part of the country, where Igbo-Ora was located.
'We eat a lot of okro leaf'
Overall, almost 5% of all Yoruba births produced twins, said the Belgian study, compared with just about 1.2% for Western Europe and 0.8% for Japan - although fertility drugs in the developed world were changing those figures.
Yam consumption might be one explanation for Africa's largesse, some West Africans and Western experts believed. Yams contain a natural hormone phytoestrogen, which might stimulate the ovaries to produce an egg from each side.
For their part, Igbo-Ora's residents appeared nonplussed about their twin phenomenon.
Some like Akinyemi supported the yam theory - and point specifically to the reputedly high oestrogen content of agida, the local name for yam tubers.
He said: "We eat a lot of okro leaf or Ilasa soup. We also consume a lot of agida. This diet influences multiple births." Others are not so sure.
Akin Odukogbe, a senior consultant gynaecologist with the University Teaching Hospital (UCH) in Ibadan, said: "The real cause of the phenomenon has not been medically found."
He said: "But people attribute the development to diet," adding that studies had shown that yam could make women produce more than one egg which could be fertilised.
Twin 'special gift'
Chief nursing officer at the hospital Muyibi Yomi, who recorded a monthly average of five twins for every 100 births, puts it all down to genetics.
She said: "If a family has a history of multiple births, this will continue from generation to generation."
That should be good news for Yorubaland, where twins were regarded as a special gift from God and bearers of good luck, Akinyemi said.
He said: "Twins are treated with affection, love and respect. Their birth is a good omen."
But while many African cultures saw twins as blessed, they often believed twins also had divine powers and the ability to harm those who cause them displeasure.
In pre-colonial times some communities used to kill twins and occasionally their mothers, believing a double birth was an evil portent and that the mother must have been with two men to bear two children at once. A Scottish missionary is credited with ending this practice.
In Yorubaland and indeed in large swathes of sub-Saharan Africa, twins were also believed to possess one soul between them. This belief accounted for a whole series of distinctive, and in some cases macabre rituals that were often country specific.
