Part of genetic diversity is the apparent fact that some partnerships have only girls or only women as descendants. This is the message of a study published in Science Advances by Wang et al. on 2025-7-18. The commonly assumed binomial distribution where each event has an equal chance of occurrence at each new point in time does not necessarily hold for this particular events. Therefore, the search for a genetic explanation has been going on for some years. Therefore, there might be a potential for an epigenetic explanation as well, as environmental conditions might co-determine the expression of genes in both parents. The research will surely continue and the sex and gender diversity offers still a lot of surprises. A sociologist’s perspective would tend to focus on later gender attributes and choices rather than sex at birth. The bio-psycho-social research agenda remains wide open.
