Who pays for dinner when dating?

My young niece recently came out and asked me who pays the check on a first or second date. I've heard the general practice in both hetero and gay dating is the one who asked first usually pays but I'm pretty out of the loop on this.

My niece says most of her dates seem to sit back and wait for her to pick up the check. For example, if she buys her date dinner, her date doesn't reciprocate by paying for movie tix. What is the general consenus on this? Do you go 50/50 in your early relationships or wind up paying more or less? I know some women are shy about talking about money or don't want to appear cheap.

Women I know in marriages usually go half and half on expenses but I'm not sure about the early dating stages. Advice please.