nonsense, of course.
Nuns might have a higher rate of endometrial uterine cancer but their rate of cervical uterine cancer is almost nil.
Endometrial cancer is usually low grade and has a high cure rate in postmenopausal ladies.
There is a more aggressive type of endometrial cancer in obese women with few periods and infertility that occurs in middle age, and I often advise these women to go on the pill to regulate their periods so they lower their risk of getting cancer.
and there is an aggressive type that occurs in younger AfroAmerican women.
Cervical cancer is higher in women with more sexual partners. (it can occur in a monogamous married lady, but statistically the risk is higher in the promiscuous).
Thanks to the Pap smear, it is usually caught early and cured. without a pap smear it would be epidemic.
Yet other diseases are less common in nuns.
Nuns don’t smoke, so they don’t often die of the most common cancer that kills women: Lung cancer.
And they tend to have less diabetes due to a decent diet, so they live longer.
Breast cancer is higher in women who don’t breast feed and who have their children later in life. Yet other things such as obesity and hormones and genetics influence breast cancer, I’m not sure if taking the pill would make a difference.
and of course breast cancer is higher in older women, and most nuns live to a ripe old age due to their healthy life style.
Today, the world's 94,790 nuns still pay a terrible price for their chastity because they have a greatly increased risk of breast, ovarian, and uterine cancers: the hazards of their nulliparity.
Alternative explanation: Women from a demographic that has a higher incidence of the mentioned cancers are more likely to become nuns than the population at large.
I also can’t imagine that with an average birth rate of 2 children among most women that the benefits of pregnancy and lactation offer higher protections in a life span of 76+ years average.