If your partner is cheating on you, blame it on his or her genes, says new research in Britain.

The study, billed as Britain's biggest survey of sexual and other behaviours carried out by St. Thomas's Hospital in London, also holds genes in a person responsible for his/her spirituality, sleeping disorders and even snoring.

Led by Tim Spector of St. Thomas's Hospital involving 10,000 identical and fraternal twins, the research tries to argue that it is possible to pinpoint the role of genes and environment in determining human behaviour.

Spector argued it could become possible to gauge if a person has a tendency to be unfaithful. In the confidential survey, people's disposition towards credulity and betrayal was attempted to be measured and it was found that 40 percent of infidelity could be attributed to the whims of genes.

The survey "tracked down" the genes to three chromosomes but couldn't link infidelity with a gene supposedly responsible for variation in human sexual behaviour.

The survey showed that men desired more partners than women and the Y chromosome, found only in men, was a great influence in this.

According to Spector, so far studies on animals had shown a connection between genetic influence and infidelity, but this was the first study on human behaviour. The result of the survey would be published in the next issue of Twin Research.

The survey had female twins with an average age of 50 answer questions about infidelity, their attitude to it and the number of sexual partners. The confidential survey showed that the respondents had an average of four to five partners, but only 20 percent admitted to being unfaithful.

Spector was quoted as saying in the Daily Telegraph: "This is surprising. It means, for example, that if one twin had an affair, the risk that the other would do the same was doubled. For non-identical twins, the risk went up one and half times."

In the case of spirituality, genes were seen to be determinant in deciding whether a person would believe in god, but the desire to go to church was an influence of one's environment.

The survey said almost 50 percent of sleeping disorders like snoring could be linked to genetic influences. Sleeplessness and restless legs were also seen as inheritable.

Spector felt the new find could pave the way for newer treatments.

--Indo-Asian News Service