Women with polycystic ovary syndrome (PCOS), a common hormonal disorder that can cause irregular menstrual periods among other things, have finger length patterns similar to that of men, according to a new study from Australia.

Finger length patterns differ between men and women. In men, the second finger is shorter than the fourth finger, while in women this difference is not evident, note Fleur R. Cattrall from Monash University in Melbourne, Victoria, and her colleagues.

The disparity might be explained by differences in the hormones that men and women are exposed to before birth, the researchers explain in their paper in the December issue of Fertility and Sterility.

This idea is supported by the fact that women with conditions characterized by elevated levels of the male hormone testosterone during fetal development often have a masculine finger length pattern.

To determine whether women with PCOS have masculine finger length patterns, Cattrall’s group conducted a comparison study involving 70 women with PCOS and 70 women without the condition, between the ages of 18 and 40.

The investigators measured the second to fourth finger length ratio on the palms of the left and right hand. Compared with the other women, PCOS patients had finger length patterns on the right hand that more closely resembled those of men.

The team suggests that the masculinized finger length pattern they identified could be considered evidence of testosterone exposure in fetuses destined to develop PCOS.

SOURCE: Fertility and Sterility, December 2005.