The intimacy of it was higher than the food and many other needs. About it tell results of research of scientists from the University of Rochester.
They conducted an experiment with round worms. Animals-males were asked to choose between serving food and the fertilization of another worm. The majority of males chose the second option.
Scientists suggest that the collected data can be easily transferred to men. A number of other researchers looking at this venture with skepticism. Plans for more accurate research in this area scientists are not reported.