In 1993, Dean H. Hamer and colleagues in the US published results from their research that indicated that men with speicifc genes were more likely to be homosexual than were men without those genes. The study hypothesized that some X chromosomes contain a gene, Xq28, that increases the likelihood of an individual to be homosexual. Prior to those results, researchers had argued that the cause of homosexuality was environmental and that homosexuality could be altered or reversed. Hamer’s research suggested a possible genetic cause of homosexuality. The study inspired further research into biological mechanisms of homosexuality.

During the twentieth century in the United States, Bernadine Patricia Healy was a cardiologist who served as the first female director of the National Institutes of Health or NIH and the president of both the American Heart Association and the American Red Cross. Healy conducted research on the different manifestations of heart attacks in women compared to men. At the time, many physicians underdiagnosed and mistreated coronary heart disease in women. Healy's research illustrated how coronary heart disease affected women. Healy was also the deputy science advisor to the United States president Ronald Reagan, and during her time at the NIH, she founded the Women's Health Initiative. That initiative was a $625 million research study that aimed to determine how hormones affected diseases specific to postmenopausal women. Through her research and leadership positions, Healy helped improve women's healthcare in the US and helped expand the resources available for research into women's health.