This Funny Lesbian Joke

If vampires love blood, why don't vampires drink period blood? The big question here is, why doesn't Edward Cullen attack Bella on her period?! No top vampire book author could give a logical explanation in this regard. Stephanie Meyer, the author of Twilight book series, once said that vampires are not attracted to period blood because it's not fresh. Many people didn't agree, though. How can someone call that blood stale when a vampire can slurp it right off the tap?!