Transgender hormone therapy (male-to-female) males is associated with higher serum estrogen. Both estrogen and testosterone help to stimulate bone formation, especially during puberty. Estrogen is the predominant sex hormone that slows bone loss, even in men. In spite of the induction of breast development, transgender women who undergo HRT do not have an increased risk of breast cancer. Only a handful of cases of breast cancer have ever been described in transgender women who have undergone male-to-female HRT. This is in accordance with research in cisgender men in which gynecomastia has been found not to be associated with an increased risk of breast cancer,
Sexual Preference (book) that while Bell "et al."′s suggestion that biological factors have a stronger influence on exclusive homosexuality than they have on bisexuality may seem plausible, it has not been directly tested and appears to conflict with available evidence, such as that concerning prenatal hormone exposure. The psychologist Bruce Rind credited Bell "et al." with disproving psychoanalytic theories about the development of homosexuality, along with the idea that childhood seduction causes homosexuality. The psychologist Mark Yarhouse wrote that while "Sexual Preference" is cited by proponents of a biological explanation, it relies on retrospective memory recall, which can be unreliable. The psychologist J.