Originally Posted by
GrumpyDiver
There is no "have to" in photography; these are compositional choices that the photographer makes in keeping with the image he or she is trying to create.
In portraiture, deliberate softness is often aimed at females, especially their faces, to reduce what might be viewed as blemishes, wrinkles, etc, which often become more prominant was people age. This softness has evolved to a point where is seems to represent femininity, regardless of the age of the subject, even getting down to children. In general, regardless of the amount of softening applied; we do want certain features to remain sharp; eyes and potentially the lips come to mind here; but we will tend to hide the acne and other defects in teen girls.
On the other hand, the opposite seems to be true for men; where sharp focus that show sculpted muscles, facial hair, etc are often enhanced to represent masculinity. Even as men age, wrinkles and scars are viewed as "badges of honour", that are worn with pride and not hidden with artifical softening.
There is a bit of a crossover when photographing / displaying women engaging in more "traditional" male roles; athletic and business poses are handled (within limits) with a more masculine style; accentuating starkness and downplaying defects without softening the image. Street photography or photojournalic styles, where we want to portray a bit more grittiness will try to show the subjects, both male and female, with wrinkles and blemishes. On the other hand, ballet or dance images may emphasise a softer view, regardless of the gender of the subject.