first, even without the existence of religion taking a life should not sound normal.

Aquinas believed that human nature is essentially good, and that all humans are oriented towards perfection and good acts. Humans do not have a natural tendency to commit evil or sinful acts. Instead, any wrong or sinful acts that may be carried out are due to mistaking a wrong act for a right act.

there are conditions one finds himself and would have no other reason but to take a bad decision( at that moment the bad decision becomes the right thing at that time) the bad decision becomes pro choice whereby the situation at hand makes a person choose pro choice.
most times pro choice comes as a solution when the situation at hand becomes a ugly one.

It should be normal for one to choose pro life but pro choice is considered mostly when there is a problem at hand these problems can be unwanted pregnancy, results from extra marital affairs or having an affair with a person you have no plan of having children with.

so i will conclude that situations determine but pro life should be the norm.