Biologically speaking, facial hair are a vestigial trait  from a time when humans had hair on their face and entire body like the apes. With human evolution, facial hair loss has become more convenient, and is more prominently seen among the indigenous Americans and some east Asian populations. However, when you leaf through the pages of history, most of the cases of male beards are widely influenced by the societal attitudes such as cultural-religious traditions and the ever-evolving fashion trends. Beards signify slow, seismic shifts dictated by deeper social forces that shape and reshape ideals of manliness. Before Alexander the Great (who was clean-shaven), for instance, all Greek men had beards. After him, they were all clean-shaven. It is mandatory for some religion like Sikhism to have a full beard. Other cultures, even while not officially mandating it, view a beard as a central to a man’s virility.

In ancient India, the beard was allowed to grow long, a symbol of dignity and of wisdom. The nations in the east generally treated their beards with great care and reverence, and the punishment for licentiousness and adultery was to have the beard of the offending parties publicly cut off. They had such a sacred regard for the preservation of their beards that a man might pledge it for the payment of a debt.

Now I do not know about the virility factor in this case, though I did saw some really interesting representation of virility and sexual prowess in Rajasthan emphasizing highly on that fact.