How do you hold up doors for others in Americaland?!? In Sweden we usually position ourselves so that it's obvious you expect the next person to "catch" the door, then when that person has "caught" it, you let go and move on, so you hold the door for the one after you - regardless of gender - and that's it. It's like a relay race, but with a door. Some idiots don't participate, but generally I think Swedes are pretty good at holding doors for eachother, and particularly at my university. Maybe that's because the main building mostly concists of corridors full of doors. *shrugs*
About the clothes as a reason for "chivalry", I've lived rough wilderness life in 14th century style dresses, I've carried a heavy standard in full ball gown regalia: high heel shoes, nylons, fluffy underskirt, gloves, silly hat. No problem. No problem at all. There are
very few things I can do wearing trousers that I can't do in a dignified manner wearing a skirt. Like climb between rows of seats in lecture halls.
Anyways, I prefer common courtesy equal to all over chivalry. Because nobody wants the door in the face and if everyone holds the door for the next person, nobody will get the door in the face and nobody will be left holding the door for ages.