While I believe adoption should be the preferred choice, I would never say that because a woman's "conjugal" love cannot produce a child, she can never have children. What about those who want to get pregnant and can’t?
So often these days we deal with the argument that a woman has a right to choose to not have a baby—regardless of the fact that it is already in her womb. Now you are suggesting that a woman has a right to have a baby regardless of how the baby is conceived.
Simply because we want something does not mean that we have a right to it. We are not the center of creation; God is. It is God who decides what our rights are. It is he who has the right to determine how we are to use it, and he has.
For those having difficulty conceiving, it can be a tremendous hardship and sorrow. But skirting the moral law is not the answer. There are licit means to enhance fertility or overcome obstacles that inhibit conception. And as you mentioned, there are many children in the world looking for parents to love them through adoption. Trusting God and working within his laws is the way to approach any challenge we are presented with in life.