Evolutionary biologists have since taken the concept further. If someone can do difficult things, not only carrying peacock tail feathers or a long dark lion mane, but also things that require much practice without contributing to physical fitness and survival, and yet stay alive, that individual must have especially good genes.
进化生物学家自此发展了这一概念。如果有人能做有难度的事情，不仅能长出孔雀尾翎或狮子长长的黑色鬃毛，而且能够处理需要更多练习却无助于身体健康和生存的事情，并且能够生存下来，该个体一定拥有极好的基因。它们因而具有性别魅力。