Morality, by its nature, is not obligatory. Morality is a value judgement, and people do not necessarily share values. Your values may require you to only have sex inside of heterosexual marriage. Mine may not. You have no right to dictate to me what my values must be, any more than I have the right to dictate yours.

In your value system the fetus may have equivalent rights to an infant or to an adult. In my values infants do NOT have equivalent rights to adults, nor do children. Children have greater rights to bodily autonomy than do infants, and adults have greater autonomy rights than do children.

In all these cases the "rights" do not actually exist outside of the formal codes and enforcement of a state. Even in a state the actual nature of rights is often in conflict and flux...my grandmother didn't have the right to vote until the 19th amendment, my mom didn't have the right to independently procure a credit card until the '70s.

You can not dictate to me what my "duty" entails, any more than I can dictate to you, nor can you decide for me what "is certainly better for everyone", not unless you feel entitled to be a dictator;)