"There is no definitive proof that she did indeed sleep with Culpepper, whereas she did admit to having slept with Francis Dereham due to a precontract between the two, in other words, they intended to marry.

That being said though, I've often wondered why the question of Kathryn's fertility has never come up in the past. Where Henry VIII is concerned, he might have been at fault, but with Dereham, who was much younger, there is no such excuse.

I do tend to believe Kathryn was sterile, but there doesn't seem to be any evidence to support it in anything I've read concerning her. Her inability to conceive children by Henry AND by Francis are the only two things that lead me to this conclusion. Though, if her use of contraceptives in the form of inserting stones into her vagina is to be believed (I do not give any credence to this rumour), then it seems plausible she did the damage to herself."

"she was young and ripe, she could have a least gotten knocked up by Culpepper...was she damaged goods?"

"I think Juliana nailed this with her post. As for Katheryn using small stones....this is not out of the bounds of possibility. It is known that during Tudor times, barrier methods like wooden blocks, small stones and beeswax were used as cervical caps."