Women are instinctively attracted to genetically different men, and disrupting that attraction could result in difficulties when trying to conceive, an increased risk of miscarriage and long intervals between pregnancies, according to the researchers from the Universities of Liverpool and Newcastle. And passing on a lack of diverse genes to a child could also weaken their immune system later on.

Humans choose partners through their body odour and tend to be attracted to those with a dissimilar genetic make-up to themselves, maintaining genetic diversity; so it’s our genes that determine who we find attractive.

The researchers asked one hundred women to sniff six sweaty men’s t-shirts, before and after starting to take the contraceptive pill.

“The results showed that the preferences of women who began using the contraceptive pill shifted towards men with genetically similar odours,” said researcher Dr Craig Roberts from Liverpool University.

And he added that being tricked by your pill into choosing a genetically similar partner could not only lead to fertility problems, but it could ultimately lead to the breakdown of relationships when women stop using the contraceptive pill, since odour perception plays a massive role in maintaining attraction to partners.

Previous studies have also found that being on the contraceptive pill messes with the signals women’s own pheromones let off. Normally, when a woman is at her most fertile she gives off an extremely attractive scent, to the point where research shows she is judged to be more physically attractive, stylish and confident that at other times of the month. But being on the pill puts those pheromones out of whack. To find out more, Click Here.