Marriage, various people including Archbishop Sentamu have said, is about the procreation and education of children.

Therefore no-one who is infertile by reason of illness, injury or age can contract a valid marriage.

That includes anyone infertile by reason of treatment for cancer and all women over the age of menopause.

Of course, if a heterosexual couple marry and subsequently discover that one of them is infertile, the marriage will be annulled.

On the other hand, if you find this logic too harsh and think that heterosexual couples should be able to marry, even if one of them is infertile and there is no possibility of procreation, by what logic do you deny marriage to same-sex couples?