Contributors to the development of homosexuality may include: Direct alteration of hormones during fetal development, use of drugs that impact androgens (e.g., Depo-Provera, diazepam, marijuana), maternal severe emotional stress (stress hormones may cross the placenta and interfere with testosterone production in the baby), immune reaction against chemicals necessary for sexual differentiation. (Wilson, Glenn. The Great Sex Divide. p 78-80. England: Peter Owen Publishers, 1989.)