Rape as a Reproductive Strategy: Fact or Fiction?

This entry was written by Rowena McPhee as part of a project done in BIAN 2133 ‘Human Reproductive
Strategies’ at The Australian National University in 2019 Semester 2.


Sexual selection may be used to describe a range of human behaviours, from polygyny to sexual coercion. The theory of sexual selection can explain the evolution of behaviours and physical adaptations that increase the chances of successful mating with the result of passing genes on to subsequent generations. As such, some argue that rape has evolved via sexual selection, as the males who used rape as a reproductive strategy may have had greater reproductive success than those who failed to mate. In this essay, I will outline the main argument supporting rape as a mechanism of sexual selection, followed by the main argument supporting rape as an expression of power. I will then consolidate these arguments by providing evidence for the evolution of rape as an expression of power. Finally, I will discuss the naturalistic fallacy and its relation to studies of evolution.

Main Text

Rape as a Mechanism of Sexual Selection

Many human behaviours have an evolutionary basis, and some evolutionary biologists, such as the Thornhills and Shieldses (1982) suggest that sexual coercion, or rape, is one such behaviour. The two pairs of academics engaged in some debate over the specifics, such as whether rape is an adaptation in its own right or the by-product of a different adaptation, and whether rape is a facultative response to circumstances or an activity inherent to all males; however, there was broad agreement between them that rape is an adaptation with an evolutionary basis. Thornhill and Thornhill posited that rape may be a reproductive strategy used by men who are otherwise unable to compete in circumstances of contest competition, and may have evolved through sexual selection; that is, they suggest that rape has evolved as a reproductive strategy. Thornhill and Palmer’s (2000) inflammatory approach to explaining the evolutionary basis of rape further supports this model of rape as a sexually motivated activity, while simultaneously denouncing the perspectives of social scientists and feminist theorists.

Rape as an Expression of Power

Social scientists and feminist theorists tend to disagree with the Thornhills and Shieldses, suggesting instead that rape is an act of power and domination, not an act of sex. Feminist author Susan Brownmiller, for example, argues that ‘[rape] is not a crime of lust but of violence and power’ (Brownmiller, 1975). If the Thornhills and Shieldses are correct in their assessment that rape has evolved as a mechanism of sexual selection, then we would expect that the victim population should fit one of two patterns. Firstly, young, healthy and able-bodied women may be over-represented as victims of rape, as they are the most likely to be selected via mate choice. Alternatively, rape may occur indiscriminately as a result of violent behaviours that have evolved via sexual selection. However, statistics show that populations of rape victims do not tend to be healthy young women, nor are they representative of the population as a whole. Rather, populations of rape victims tend to include over-representations of pre-pubescent girls, disabled women, and Indigenous women (Centres Against Sexual Assault, 2019). That is, populations of rape victims primarily consist of people who are less powerful than the average man; this indicates that rape is not motivated by sex, but by power.

Consolidation of Evolutionary and Power Hypotheses

These two opposing viewpoints can be consolidated. The demographic evidence presented in the previous paragraph strongly supports the viewpoint favoured by social scientists and feminist theorists that rape is motivated by power, not sex. However, that does not mean that there is no ultimate explanation for rape. Smuts (Vandermassen, 2011) proposes that men may have evolved a drive for controlling women (although perhaps that may be extended to ‘controlling less powerful people’). This control may manifest in many ways – possessive behaviour, non-sexual violence, rape, and other such behaviours. As such, the argument can be made that the act of rape itself did not evolve as an adaptation in its own right, but the dominating and power-grabbing tendencies that underlie rape may have evolved via sexual selection.

The Naturalistic Fallacy

It is pertinent to note that arguments and outrage against the evolution of rape or other immoral activities may rely on the naturalistic fallacy. The naturalistic fallacy encapsulates the misconception that if something is natural it therefore must be inherently good or moral (Teehan and diCarlo, 2004); on the other hand, this implies that something immoral, such as rape, cannot be a natural product of evolution. In fact, there should be no inherent value attributed to an adaptation simply because it has evolved. Therefore, the evidence presented here in support of the evolution of dominant behaviour does not mean that this behaviour is good or moral; nor are my arguments against the evolution of rape as a sexually motivated mechanism of selection formed on the misguided basis that rape is immoral and therefore cannot be the product of evolution. Arguments suggesting that rape and violence are inevitable and should be excused simply because they may have an evolutionary basis are not only misguided, but also dangerous.


Although there is a sound theoretical basis for the evolution of rape as a mechanism of sexual selection, I have used demographic data on populations of rape victims to show that rape cannot be fully explained as a mechanism of sexual motivation. Rather, this data supports the thesis that rape is used as an expression of power, and that these dominant and power-grabbing tendencies may have evolved through sexual selection. My arguments, that aim to consolidate the evolutionary theories of biologists and the power theories of feminists, do not claim that sexual coercion is in any way justifiable due to its possible evolutionary basis.

Reference List

Brownmiller, S. (1975). Against Our Will: Men, Women and Rape. New York City: Simon & Schuster.

Centres Against Sexual Assault (2019). Fact Sheet: Statistics about sexual assault. CASA Forum. Victorian Centres Against Sexual Assault.

Teehan, J. and diCarlo, C. (2004). On the Naturalistic Fallacy: A Conceptual Basis for Evolutionary Ethics. Evolutionary Psychology, 2(1).

Thornhill, R. and Palmer, C. (2000). A natural history of rape: Biological bases of sexual coercion. Cambridge: The MIT Press.

Thornhill, R. and Thornhill, N. (1982). Human rape: An evolutionary analysis. Ethology and Sociobiology, 4(3).

Vandermassen, G. (2011). Evolution and Rape: A Feminist Darwinian Perspective. Sex Roles, 64(9-10), 732-747.

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