Evidence inconclusive. On one hand, a guy who just wants sex will certainly try and seal the deal on the first date. Although guys who just want sex don’t usually go the traditional date route when there are so many bar skanks to be had.
On the other hand, a guy who’s legitimately interested in a relationship with you also wants to have sex with you on the first date. Make no mistake, if he could order that from the Chili’s Menu, he’d buy three.
However, a guy who wants a relationship will usually pretend he DOESN’T want to have sex on the first date, so that you can’t be creeped out by how incredibly horny he is until it’s too late to back out gracefully. See, us relationship-wanting guys are always two steps ahead.
Unless the date goes really well, and they feel like trying for sex on the first date isn’t going to jeopardize anything, or if you’re both twice-divorced and in your fifties and just sick of all this dating bullshit.
Hopefully some of those immutable dating laws (ie, my casual observations) will help you determine whether or not to have sex with the guy I imagine has been waiting quite a while while you stall in the ladies’ room, iPhone in hand, waiting for a response to this question.