The following is from the genetic testing company 23andMe. Homosexuality is strictly choice-driven by environmental factors.
A recent 23andMe analysis did not find any variants associated with sexual orientation.
Sexual orientation of 23andMe users
No genetic markers found associated with sexual orientation
Studies have suggested a person’s sexual orientation can be influenced by genetic and environmental factors. However, our analysis did not find any genetic associations. Future research may refine our understanding of how genetics might affect sexual orientation.