The Mary Renault Society

The Triangle Area of North Carolina

What Made Me Gay?

There are three main mechanisms that determine sexual orientation. All involve pre-natal events, i.e., while in the womb; there is no evidence that anything that occurs after birth impacts sexual orientation. The primary one involves the expression of genes that code for sex hormones and how these impact the developing brain. A secondary mechanism involves inheritance of certain genes that affect sexual development and differentiation. A minor mechanism involves the mother’s development of antibodies that block certain sex hormones from acting. Variations in these three mechanisms likely account for the range of sexual orientations. Environmental factors can affect these processes during fetal development but not after birth.

David M. DeMarini PhD

David DeMarini was born in Peoria, IL in 1950 and obtained the BS, MS, and PhD (1980) in biological sciences (genetic toxicology) from Illinois State University in Normal, IL. He did 3 years of postdoctoral research at the Oak Ridge National Laboratory in Oak Ridge, TN, and 2 more at the National Institute of Environmental Health Sciences (NIEHS) in RTP, NC. In 1985, he became a senior-staff scientist as a genetic toxicologist at the main research laboratory of the U.S. Environmental Protection Agency in RTP, NC, where he ran a laboratory for 35 years until his retirement in 2020. He was an adjunct professor at the Gillings School of Global Public Health at UNC for 35 years and lectured at Duke in the pharmacology department for 20 years, ending both in 2020. He trained 10 PhD students and 10 postdoctoral researchers and numerous visiting scientists.

He has published >200 scientific papers and 20 book chapters; his work has been cited >16,000 times. He has lectured, taught, and organized conferences in 55 countries and throughout the U.S. He has served on numerous national (e.g., National Academy of Sciences) and international (WHO) panels on environmental causes of cancer. He is a coauthor of several of the Surgeon General’s Reports on Smoking and Health, and he has served on 10 WHO panels that determined various agents to be human carcinogens, including cigarette smoke (1985, 2004), diesel exhaust (2014), indoor air pollution (2010), outdoor air pollution (2016), and firefighting (2023).

He is past present of the national and international chapters of the Environmental Mutagenesis and Genomics Society, was Editor-in-Chief for 21 years (until 2019) of Mutation Research Reviews (impact factor 7), and he has received the highest awards given by various institutions/organizations. His main research area has involved determining the mutations in DNA caused by various environmental carcinogens and identifying those mutations and mutational mechanisms in human tumors.

Outside of science, he has co-founded two theater companies, plays piano, and enjoys cooking and traveling.


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