The situations aren't entirely parallel. The official teachings of the RC Church on BC remains unchanged and Catholics on BC are objectively disobeying their religion. However, actual documents and catechisms on the Bible written by church authorities and disseminated in Church media actually often state the exact opposite of what the old documents did, thus indicating a change in the "unchangeable" doctrines of the Church. And if you ask them why, they'll tell you these old doctrines had to be changed because they have been disproven.
What else will be discarded when it has been disproven, eh?
“What else will be discarded when it has been disproven, eh? “
The sanctity of life is a dogma. Not everything in the church is a dogma.
Don’t be so quick to think Catholics don’t follow it. I had two C-sections in nine months at great risk to my own life because of that belief in the sanctity of life.