Most homosexual orientation develops during gestation. Patterns tend to be firmly in place by age 5. Discusses lack of success of change therapies (e.g., push bisexuals to confine behaviors to opposite sex only, or enforce celibacy, or push the individuals to attempt suicide). (Pease, Barbara and Allan. Why Men Don’t Listen and Women Can’t Read Maps. p 171-186. NY: Broadway Books, 1998.)

The brain areas of males and females related to sex differ. Genes create the basic template, primarily during gestation, that is acted upon by hormones. (Carter, Rita, Ed. Mapping the Mind. p 73. CA: University of California Press, 1998.)

The brain is hard wired during gestation. Differences are most noticeable after puberty when the brain becomes fully activated as a result of being bathed in hormones. (Howard, Pierce J., PhD. The Owner’s Manual for the Brain. p 215-221. GA: Bard Press, 1994, 2000.)

Study: Females had 6 times the chance of birthing a gay son if the mothers experienced severe stress during early pregnancy. Stress, sickness, and some medications tend to suppress testosterone levels. (Pease, Barbara and Allan. Why Men Don’t Listen and Women Can’t Read Maps. p 181-186. NY: Broadway Books, 1998.)

Sexual preferences are partly determined by hormones before birth. Typically there are higher numbers of male homosexuals over lesbians (e.g., more opportunities for something to “go wrong” in the process of converting the standard female embryo into a sexually competent male). (Wilson, Glenn. The Great Sex Divide. p 80-81. England: Peter Owen Publishers, 1989.)

Androgen Insensitivity Syndrome or AIS is a condition where an individual has male internal organs with a vagina. AIS may be seen in a chromosomally normal male who had reduced sensitivity to masculinizing hormones during gestations. (Seligman, Martin E P., PhD. What You Can Change…and What You Can’t. p 148-173. NY: Fawcett Books, 1993.)

Study: testosterone injected into pregnant guinea pigs during 30th-65th day of gestation resulted in the birth of masculinized female young. As adults they showed more masculine components in sexual behavior patterns. The effects of androgens administered during pregnancy were permanent. (Foss, B.M., ed. Brain and Behavior 1, Mood, States and Mind. p 394-395. Britain:Penguin Books, 1969.)

The term “life-style choice” is sometimes used by individuals who do not want to acknowledge the biological (e.g., genetic and chromosomal) basis of homosexuality. (Gurian, Michael. The Wonder of Boys. p 231-233. NY: Jeremy P. Tarcher/Putnam, 1996.)

Sexual preference is set in the human brain about 6-8 weeks after conception. Theoretically, at least, this could be controlled with hormones during fetal development. (Pease, Barbara and Allan. Why Men Don’t Listen and Women Can’t Read Maps. p 180-186. NY: Broadway Books, 1998.)

Because it is based on the impact of male hormone on the brain during fetal development, homosexuality is mostly genetic rather than a choice. The genetic combination of red hair and freckles occurs at the same rate as homosexuality. (Pease, Barbara and Allan. Why Men Don’t Listen and Women Can’t Read Maps. p 171-186. NY: Broadway Books, 1998.)

“Nobody in science now believes that sexual orientation is caused by events in adolescence ... Homosexuality is an early, probably prenatal, and irreversible preference.”  ―Author and Geneticist Matt Ridley. Summary of 14 studies that show brain and body differences between heterosexual and homosexual individuals (e.g., inner ear, finger lengths, finger ridges, startle reflex, maternal side, etc.). Ontario Consultants on Religious Tolerance. Religious Tolerance.org    http://www.religioustolerance.org/hom_caus4.htm