Cuckoldary is rare in humans!
Human behavioral scientists argue that extra-pair copulation is adaptive in human females, as through extra-pair copulation, women can acquire good genes from other potential mates. This is suggested because it is found that women experience greater sexual attraction to particular extra-pair men, but not their own partners, during their highest peak of fertility (Gangestad & Thornhil, 2008).
However, recent genetic evidences cast doubt on such arguments and suggest that the rate of cuckoldry is very low in humans (around 1 percent). To achieve historical records on cuckoldry, scientists compare family specific Y chromosomal variation between men that based on genealogical evidence, are patrilineally related. “The surprising result of these new studies is that human extra-pair paternity rates have stayed near-constant at around 1% across several human societies over the past several hundred years” (Larmuseau et al., 2016). Greeff and Erasmus (2015) also showed that genetic analysis in Afrikaner families in South Africa shows 0.9% rate of cuckoldry and argued that “given the current data on historical populations we have to conclude that, at least for Western human populations, cuckoldry rate is probably in the range of 1%”.
So what does it mean? Does the rarity of cuckoldry in human historical records mean that women do not look for potential mates with good genes, or it simply means that human men are good in mate retention and anti-cuckoldry tactics? That’s the question that should be considered now.
Gangestad, S., & Thornhill, R. (2008). Human oestrus Proceedings of the Royal Society B: Biological Sciences, 275 (1638), 991-1000 DOI: 10.1098/rspb.2007.1425
Greeff, J., & Erasmus, J. (2015). Three hundred years of low non-paternity in a human population Heredity, 115 (5), 396-404 DOI: 10.1038/hdy.2015.36
Larmuseau MH, Matthijs K, & Wenseleers T (2016). Cuckolded Fathers Rare in Human Populations. Trends in ecology & evolution, 31 (5), 327-9 PMID: 27107336