MedicalResearch.com Interview with: Jianzhi "George" Zhang
Marshall W. Nirenberg Collegiate Professor
Department of Ecology and Evolutionary Biology
University of Michigan
Ann Arbor, MI 48109-1085 MedicalResearch.com: What is the background for this study? Response: A few percent of humans perform same-sex sexual behavior (SSB), a trait that is partially heritable. Because SSB leads to fewer children, the stable maintenance of SSB-associated alleles in populations has been a long-standing Darwinian paradox. A number of hypotheses have been proposed to resolve this paradox, but most of them lack clear empirical evidence. One version of the antagonistic pleiotropy hypothesis posits that SSB-associated alleles are subject to heterosexual advantage. Specifically, it was found that SSB-associated alleles are associated with more sexual partners when in heterosexuals (individuals of exclusive opposite-sex sexual behavior), which could lead to more offspring, potentially compensating the reduced reproduction of SSB individuals. While the above mechanism has likely worked in premodern societies, our recent study (PNAS 2023) found that it is no longer working in the modern United Kingdom, because the widespread use of contraception has decoupled the number of offspring from the number of sexual partners in heterosexuals. (more…)