The Science of Sexual and Gender Diversity

Diversity in Human Sexuality

Produced by the Association of Science in South Africa, this is an accessible but comprehensive interdisciplinary  guide to the science of sexuality, freely accessible on-line in PDF form.

The introduction to the report notes that while two thirds of the world no longer prohibits LGBTI relationships, some countries in Africa, and also Russia and India, are introducing new laws to prohibit homosexuality or its “promotion”. As much of the political push in Africa against homosexuality makes an appeal to science for support, its important that science investigate and accurately present the evidence.  It finds, as others have done, that these findings do not in any way justify social opposition.  On the contrary,

There is evidence that such new laws precipitate negative consequences not just for LGBTI persons and communities, but also for societies as a whole, including the rapid reversal of key public health gains, particularly in terms of HIV and AIDS and other sexual health programmes, increases in levels of social violence, some evidence of reduced economic growth, and the diversion of attention from sexual and other violence against women and children.

Criminalization of homosexuality thus does not protect society – it endangers it!

These findings are important too, to counter religious opposition from the Catholic Church, which claims to “respect” the findings of science – but totally ignores the science of sexuality and gender, which is that same-sex relationships are entirely natural and not in any way pathological or “abnormal”. Science also contradicts the Catholic Church’s presentation of human sexuality in simplistic binary terms:

Examining the biological factors, including genetic, neurohormonal and other factors, the report concludes that contemporary science does not support thinking about sexuality in a simple binary opposition of hetero/homosexual and normal/abnormal. Rather, it favours thinking in terms of a range of human variation, very little of which can justifiably be termed abnormal. As variation in sexual identities and orientations has always been part of a normal society, there can be no justification for attempts to ‘eliminate’ LGBTI from society.


Executive Summary

1 Introduction and Background
1.1 Terms and Concepts used in this Report
1.2 Understanding Sexual Orientation
1.3 Ethical and Human Rights Considerations

2 What is the Evidence that Biological Factors Contribute to Sexual and Gender Diversity? To what Degree is the Wide Diversity of Human Sexualities Explained by Biological Factors?
2.1 Family Studies
2.2 Twin Studies
2.3 Genetic Linkage and Full Genome Studies
2.4 Epigenetics: Early Evidence and Promising New Leads
2.5 Evolution and Genetics
2.6 Choice and Immutability
2.7 Pervasiveness and Frequency
2.8 Neurohormonal and Other Biomedical Theories: The State of the Science in 2015

3 Do Environmental Factors such as Upbringing and Socialisation Explain the Diversity of Human Sexuality?
3.1 The Development of ‘Homosexuality’ as a Category/Condition
3.2 Prominent Theories about the Role of Upbringing and Parenting in the Development of Same-Sex Orientation

4 Is there Any Evidence for Same-Sex Orientations being ‘Acquired’ through Contact with Others, i.e. through “Social Contagion”?

5 What Evidence is there that Any Form of Therapy or ‘Treatment’ can Change Sexual Orientation?

6 What Evidence is there that Same-Sex Orientations Pose a Threat of Harm to Individuals, Communities, or Vulnerable Populations such as Children?

7 What are the Public Health Consequences of Criminalising Same- Sex Sexual Orientations, and Attempting to Regulate the Behaviour/ Relationships Related to Some Sexualities Orientations?

8 What Research can be Conducted to Address the Most Critical Unanswered Scientific Research Questions Regarding the Diversity of Human Sexualities and Sexual Orientations in Africa?

9 Conclusion
9.1 Role of Biological Factors
9.2 Role of Environmental Factors
9.3 Acquisition of Sexual Orientation through Social Contagion
9.4 Change of Same-Sex Orientation through Therapy
9.5 Threat Posed by Same-Sex Individuals
9.6 Public Health Consequences of Criminalising Same-Sex Orientations

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