Your sister was correct. Implied Catholic theology basically says that sex without being open to child birth is evil. As a cradle Catholic, I had my tubes tied after our second trial because both my wife and the baby almost didn't survive. That was quick and easy with no complications. We have never regretted that decision.
When I see the same protestors working to protect living children and members of religious orders who were abused by the church, then I might start listening to them again. Today, in my book, they are false prophets.