London: Eating probiotic yoghurt calms upset tummies and does more besides - it could boost your virility as well, say scientists from the Massachusetts Institute of Technology (MIT).

They found male mice fed the vanilla-flavoured dessert had a certain 'swagger' when they walked. These mice had testicles that were five percent higher than other mice on a normal diet and 15 percent heavier than junk-eating males.

Besides, in mating experiments yoghurt-eating males inseminated their partners more quickly and produced more young than control mice, not on a yoghurt diet. The findings could have implications for human fertility and the team will next look at the association between yoghurt and semen quality in men, the Daily Mail reports.

In a bid to prove whether yoghurt could help stave off age-related weight gain in humans, MIT researchers Eric Alm and Susan Erdman fed pro-biotic vanilla yoghurt to mice with some unexpected results.

The yoghurt-eating mice had shinier fur than their non-dairy fed siblings and the male mice were described as all of a sudden having a 'swagger'. "We knew there was something different in the males, but we weren't sure what it was at first," Erdman said.

"You know when someone's at the top of their game, how they carry themselves differently. Well, imagine that in a mouse," added Erdman. Other beneficial effects included slimmer bodies and shinier fur in both sexes as yoghurt-fed mice had 10 times the active follicle density of the control group.