for a fully able bodied woman (like myself) i would appreciate it as a kind and gentlemanly gesture if it happened to me, but it wouldn’t ever occur to me to expect a man to do that because i don’t need it. i would however, definitely expect a man to give up their seat for a woman if she was pregnant. and i would judge them if they didn’t. honestly regardless of gender on either side, i would expect any able bodied person to give up their seat for someone who was pregnant, elderly, disabled, etc