In primitive societies, a beard was often the sign of masculinity, but in advanced societies, the hormonal equation ceases to be meaningful, sex and gender having thankfully diverged. Men now don’t need to feel bad if they can’t grow a beard, and if they can and do, they can make the beard mean what they wish. So says Paula Marantz Cohen, who has never known her husband without a beard and whose son, 25, alternates between a five o’clock shadow and a two-day stubble. “If a beard does anything, I have concluded, it defines a man against his father.”