Sexuality and gender are topics of frequent and heated debate in the media. Conflicting positions abound, and differentiating ideological from scientifically based analysis is difficult. However, a recent comprehensive review of the literature on sexuality and gender published in the New Atlantis claims to focus solely on the scientific evidence. The lead author, Lawrence S Mayer, is a research physician and biostatistician, and the co-author, Paul R McHugh, is a psychiatrist. It seems worthy of study by all who are seriously interested in sexuality and gender.
Mayer strongly supports equality for the LGBT community. He dedicates the review to that community, “which bears a disproportionate rate of mental-health problems in comparison to the population as a whole”, hoping it will contribute to relieving their sufferings.
First some definitions. One’s biological sex is fixed from birth and cannot be changed. Almost everyone is born unambiguously male or female. Males have two different sex chromosomes, X and Y. Females carry two X chromosomes.
Biological sex correlates with body attributes; for example, males have penis and testicles and females have a vagina.
Gender is more complex, determined by the interrelationship between biological sex, internal sense of self as male or female (or both, or neither) and one’s outward presentation and behaviour related to that perception. Gender is, to a significant extent, socially constructed.
Sexual orientation refers to the gender one is sexually attracted to and can be heterosexual, homosexual or bisexual.
Gender identity refers to one’s innermost concept of self as male or female (or both or neither) and, in an estimated 0.6 per cent of adults, can be different to the biological sex assigned at birth. In such cases, some people, assisted by surgery and hormonal treatment, “transition” into the gender they identify with.
On sexual orientation, the New Atlantis paper reports that: (1) The idea that sexual orientation is an innate biological property of human beings – "people are born that way" – is not supported by scientific evidence. This does not mean the "born that way" hypothesis is wrong, simply that it is not supported by scientific evidence. (2) There is no compelling biological explanation for sexual orientation. (3) Sexual orientation seems fluid for some people over their lifetime – up to 80 per cent of male adolescents who report same-sex attraction no longer do so as adults.
Sexuality and gender identity
The conclusions on sexuality,
mental health
and social stress are that:
(1) Non-heterosexuals are at increased risk for various adverse health and mental-health outcomes. For example, such people are at twice the risk of depression and 2½ times the risk of suicide compared with heterosexuals. Lifetime suicide attempts by transgender individuals is estimated to be 41 per cent of the US transgender population compared with 5 per cent of the overall population.
(2) Stressors such as discrimination and stigma contribute to, but do not fully explain, elevated risk of mental-health outcomes for non-heterosexuals.
And the conclusions on gender identity:
(1) The hypothesis that gender identity is an innate fixed property independent of biological sex – “ a man trapped in a woman’s body” or vice versa – is not supported by scientific evidence.
(2) Adults who have sex reassignment surgery continue to have a higher risk of poor mental-health outcomes.
(3) Only a minority of children who express cross-gender identification continue to do so into adolescence or adulthood.
(4) There is little evidence for the therapeutic value of interventions that delay puberty or modify secondary sex characteristics of adolescents.
(5) There is no evidence that all children who express gender-atypical thoughts should be encouraged to become transgender – indeed, in view of (3) above, it would seem very inadvisable to do this.
Professional bodies are divided on this review. For example, the American College of Pediatricians supports the findings but the American Psychological Association does not. Some have labelled the review "anti-LGBT", for example Samantha Allen in the Daily Beast. I am not expert enough to critically adjudicate, but I have no reason to believe that Mayer and McHugh did not honestly pursue their aim "to examine the scientific evidence on sexuality and gender – what it shows and what it does not show".
William Reville is an emeritus professor of biochemistry at UCC, http://understandingscience.ucc.ie