回复：It was used to be only for MALE over 16, and still is in some

PRC citizen ALWAYS need to fill out DS 157 to get a non-immigrant visa, male or female.

currently, DS157 is needed for passport holders of
PR China, Cuba, Iran, Iraq, Libya, Russia, Somalia, Sudan and Vietnam

All other countries: All males between the ages of 16 and 45, regardless of nationality