I didn't think it was creepy that Lorelai wanted to know on what birth control Rory was (does she really want to be a grandma at 35?) or when Rory was going to have sex for the first time. I thought it had more to do with knowing that Rory is going out there and being safe rather than discussing her favourite positions. That said, the attached at the hip relationship they had is indeed creepy. I can't imagine discussing 99% of the stuff they do with my mother.