What characteristics define an attractive female face versus an attractive male face?

There are several facial features that enhance femininity with one of these being that a feminine face is characterized by a heart shape or inverted triangle; this means the lower face is narrower than the upper and the jaw is tapered.

This is in contrast to the square jawline that characterizes a masculine face. Some women have a more squared jawline due to their inherent bone structure, but some of this appearance is from enlargement of a muscle called the masseter.