The Gender Similarities Hypothesis

This page was last edited on 5 September 2020, at 15:39.

by Janet Shibley Hyde


The differences model, which argues that males and females are vastly different psychologically, dominates the popular media. Here, the author advances a very different view, the gender similarities hypothesis, which holds that males and females are similar on most, but not all, psychological variables. Results from a review of 46 metaanalyses support the gender similarities hypothesis. Gender differences can vary substantially in magnitude at different ages and depend on the context in which measurement occurs. Overinflated claims of gender differences carry substantial costs in areas such as the workplace and relationships.

The evidence:

To evaluate the gender similarities hypothesis, I collected the major meta-analyses that have been conducted on psychological gender differences.


Inspection of the effect sizes shown in the rightmost column of Table 1 reveals strong evidence for the gender similarities hypothesis. ... 78% of gender differences are small or close to zero. ...

The small magnitude of these effects is even more striking given that most of the meta-analyses addressed the classic gender differences questions.

The exceptions:

The largest gender differences in Table 1 are in the domain of motor performance, particularly for measures such as throwing velocity and throwing distance.

A second area in which large gender differences are found is some - but not all - measures of sexuality (Oliver & Hyde, 1993). Gender differences are strikingly large for incidences of masturbation and for attitudes about sex in a casual, uncommitted relationship.


The gender similarities hypothesis stands in stark contrast to the differences model, which holds that men and women, and boys and girls, are vastly different psychologically. The gender similarities hypothesis states, instead, that males and females are alike on most— but not all—psychological variables. Extensive evidence from meta-analyses of research on gender differences supports the gender similarities hypothesis. A few notable exceptions are some motor behaviors (e.g., throwing distance) and some aspects of sexuality, which show large gender differences. Aggression shows a gender difference that is moderate in magnitude.