I know that Shinto priest can get married (and even have bigger families than average), but what about Buddhist priest and/or monks ? Is there any differences between sects, or more broadly between Mahayana and Theravada Buddhism ?

I was discussing with a Japanese friend about a current TV drama at the moment where a Buddhist priest falls in love with a girl. That's why I was wondering if there was any restriction on sex for Buddhist priest, but my friend wasn't sure, and neither am I.