After the 'homo' gene a 'Whore' gene!

World Medical Journal, Vol. no.2, June 2005

Medical Science, Professional Practice and Education

Twin Studies

Twin study reveals genetic role in female infidelity

A confidential survey of more than 1,600 pairs of female twins has revealed that genetic factors have a substantial impact on how likely women are to cheat on their partner and how many sexual partners they will have.

This is the first ever study to look at the genes underlying these influences in humans.

The results of the new research – led by Professor Tim Spector, Director of the Twin Research Unit at St Thomas’ Hospital, London – were revealed by Professor Spector during a press briefing at the Science Media Centre.

Female twins from the Twin Research Unit database answered a range of questions in a confidential questionnaire relating to their sexual attitudes and behaviour. They reported previous episodes of infidelity, total life-time number of sexual partners and also their attitudes towards infidelity.

The average age of respondents was 50, their average number of sexual partners was between four and five, just over 20% admitted to infidelity, 25% were divorced and 98% were heterosexual.

Professor Spector says: “Not surprisingly, the average number of sexual partners was significantly higher among respondents who had been unfaithful compared with those who had remained faithful – a mean of eight compared with four.”

Headline findings of the research study include:

• Genes are an important influence in explaining variation between women in both infidelity and number of sexual partners – with a heritability of 41% and 38% respectively.

• Further analysis of these results failed to support the hypothesis that a gene implicated in previous research into patterns of sexual behaviour among rodents

(AVPR1A or vasopressin gene) could explain the observed variation in human sexual behaviour.

• However, the study did find some evidence that genes in three other chromosomal areas (chromosomes 3, 7, 20) could be implicated.

• In contrast, attitudes to infidelity are not influenced to any significant degree by genetic factors – environmental factors including society, education or religion prevail.

• Believing infidelity was wrong in principle prevailed even in a significant proportion of those women who admitted

having been unfaithful, highlighting the distinction between attitudes and actual behaviour. Professor Spector says: “By demonstrating the heritability of female infidelity and number of sexual partners in humans, this study justifies additional genetic and molecular research on human sexual behaviour.”

“The fact that psychosocial traits such as number of sexual partners and infidelity appear to behave as other common complex genetic traits in humans, in that they have a heritable component, lends support to evolutionary psychologists’ theories on the origins of human behaviour.”

Professor Spector believes that the logical conclusion of his team’s new research may be that infidelity and other sexual behaviours persist because they have been evolutionarily advantageous for women.

(Source: World Medical Journal)

Infidelity genes in 20% of women

Hindustan Times

Vijay Dutt

London, November 26

Men may have finally found a watertight defence for infidelity. So far, they are the ones always accused of jumping into bed with new partners. Now, a study has established that one in every five women can't resist cheating on her husband or boyfriend. Experts blame it on a set of infidelity genes".

The study was conducted in London but its results could be equally relevant for India, as the women included in the research were broadly representative of the population in social class, race and religion.

The study, led by Tim Spector at St. Thomas' Hospital, involved 1,600 pairs of female twins aged 19 to 83 and revealed that genetic factors have same influence over infidelity as they do over medical conditions. It has put the heritable element of female infidelity at 41 percent.