Promiscous mice produce sexier offspring (UPI) -- Promiscuous mice are more likely to produce "sexier" male offspring with higher levels of pheromones. A study conducted at the University of Utah and published in the Proceedings of the National Academy of Sciences has shown that mice who compete socially for their mates produce male offspring with higher urinary pheromone levels. But on the flip side, these "sexy" mice die younger. The findings show a clear link between the lifestyle of a parent and the effect it has on the offspring. "Pheromones are the language of mice," said lead author Adam Nelson. When females mate in a socially competitive environment, they program their sons to have a head start by producing more pheromones. Lab researchers usually breed mice in a secluded environment -- that is, one male and one female. But for this experiment, the biologists bred mice in a semi-nature enclosure, where the mice were free to move around and find their own mates. They also bred another set of mice in a secluded environment. The first kind of mice were labelled promiscuous and the latter monogamous. Researchers found that sons of promiscuous parents had 31 percent more urinary pheromones than other male babies. A concurrent study conducted by the same researchers showed that only 48 percent of these sexy male mice lived to the end of the experiment, while more than 80 percent of the male offspring of monogamous mice survived to the end of the experiment. Nature World News