Scientists have told how women choose a partner

According to new research from the University of Eastern Finland, the female reproductive tract may be responsible for choosing a partner.

Pregnancy has been shown to be more likely between partners carrying different human leukocyte antigen (HLA) immune genes. Accordingly, individuals are expected to choose HLA-mismatched mates.

Previous research has shown that the benefits of HLA mismatching are mediated by body odors or personal preferences. However, it was not clear whether the benefits could be based on information after vaginal sex.

Researchers have shown that the female reproductive tract is capable of mediating post-mating sexual selection for sperm from HLA-dissimilar males. This indicates that the mating bias towards genetically compatible partners occurs only after mating at the gamete level.

The researchers conducted two experiments in which they activated the sperm of several men with follicular fluid (the bioactive fluid that surrounds the oocyte). or cervical mucus of several different women. They then investigated sperm motility and other functionally important physiological changes. All participants were also genotyped for HLA.

In both studies, the results showed that the ability to fertilize and the viability of sperm strongly depend on the combination of men and women. In other words, the reproductive secretions of women have a stronger effect on the sperm characteristics of some men than others. Both experiments demonstrated that sperm performance was better in HLA-dissimilar men and women.

“These findings may be important for a deeper understanding of sexual selection and the process of fertilization in humans and other mammals, which may to help in the treatment of infertility”, the authors emphasize.