This really isn't a question, more so a thought on a possible reason Katherine of Aragon had such trouble delivering live children.
This came to me today while researching a condition that a few of my family members have: a bicornuate uterus.
This basically means that the uterus is malformed into two distinct sections (forming a heart shape) in varying degrees of severity, and this results in:
-high rates of miscarriage
-high risk of premature delivery
-high risk of weak live births (the infant doesn't have enough room to grow, so is stunted in growth and weak as a result)
And I thought to myself, this fits Katherine's situation pretty well. I mean, obviously we will never know, and it's never wise to make a medical diagnosis hundreds of years later, but I think it's a possibility.
At least two of her pregnancies ended in premature births/miscarriages, (there may have been more, as miscarriages in the first trimester were unlikely to have been recorded accurately) and of the three that were born alive, only one (Mary, obviously) survived.
"Prince Henry," I think can be dismissed as a result of high infant mortality, as he did survive for several weeks. Her last pregnancy, however, resulted in a small and weak daughter (although some sources say she is stillborn?).
Healthy infants are possible with this condition, so Mary isn't a problem with this hypothesis.
The only true problem I see with this is that Katherine's mother, grandmother, and sisters all seem to have had no trouble conceiving and bearing live children. Mary, unfortunately, can give us no information either, as she was likely past her fertile days by the time she married Phillip. This condition isn't always an inherited one, but usually there are a few other family members who show symptoms. In my family, for example, my great grandmother and my mother are both good candidates for this condition, and my cousin definitely has it.
Anyway, this is just a thought that came to me.
People always make a big deal over Henry not being able to have children, when in reality he may just have had rotten luck with the women he bedded. Katherine may definitely have had some kind of uterine malformation, in my opinion, Anne's miscarriages were quite possibly the result of the Rh factor, and poor Jane Seymour never had a chance to prove she could continue to bear him children.
[Ed. note - other threads on the reproductive issues of Henry and his wives listed below]