Genetic Considerations in Human Sex‐Mate Selection: Partners Share Human Leukocyte Antigen but not Short‐Tandem‐Repeat Identity Markers

Problem Previous studies support a role for MHC on mating preference, yet it remains unsettled as to whether mating occurs preferentially between individuals sharing human leukocyte antigen ( HLA ) determinants or not. Investigating sex‐mate preferences in the contemporary Israeli population is of further curiosity being a population with distinct genetic characteristics, where multifaceted cultural considerations influence mate selection. Method of study Pairs of male–female sex partners were evaluated in three groups. Two groups represented unmarried ( n  = 1002) or married ( n  = 308) couples and a control group of fictitious male–female couples. HLA and short‐tandem‐repeat ( STR ) genetic identification markers were assessed for the frequency of shared antigens and alleles. Results Human leukocyte antigen results showed that Class I and/ or Class II single antigen as well as double antigen sharing was more common in sex partners than in control group couples ( P  < 0.001). Married versus unmarried pairs were not distinguishable. In contrast, STR ‐ DNA markers failed to differentiate between sex‐mates and controls ( P  = 0.78). Conclusion Sex partnerships shared HLA determinants more frequently than randomly constituted male–female pairs. The observed phenomenon does not reflect a syngenetic background between sex‐mates as STR markers were not selectively shared. Thus, sex‐mate selection in man may contravene the evolutionary pressure for genetic diversity in regard to HLA .