I am of the opinion that if abortion is allowed in cases of rape or incest, "pro-lifers" have already lost the moral battle. You don't even need to include sperm and unfertilized eggs. It's okay to "kill innocent babies" depending on how they were made? But we can't take into account the simple question of whether or not the woman wants to be pregnant or should be pregnant?
In the real world, all kinds of people have sex, even people who should never become parents. Nearly everyone has sex at some point in their lives and some of this sex will result in pregnancy. Most people will start having sex long before they are able to care for a child. Babies are a lot of work to raise and not everyone is capable of that. Some people have fertility problems and can't have kids when they want to.
Real world solutions? Detailed sex ed from pre-puberty onwards; lots of low cost and easily available contraception; medically safe abortion when contraception does not work out, and lots of social and monetary support for all parents (including those who adopt) and children.
In a fantasy world, everyone--male and female-- stays completely celibate until they are financially and emotionally ready to have a child. Around age 30-35. Many people therefore never have sex. Ever. There is no rape or incest. Nobody ever gets drunk or high at a party and does something stupid and sexual.
All children are planned, wanted and cared for well by whoever produces them. There is no need for contraception or abortion because everyone is celibate unless they are ready to be parents. And no sex ed is needed in middle or high schools because nobody younger than 35 is having sex.....
Nobody has a baby to trap a partner or to move out of the parent's home. Nobody ever gets a divorce, or is abandoned by their partner after pregnancy occurs. And no pregnancy ever leads to health problems of any kind. No parent ever gets a mental illness, a chronic disease or dies before their child becomes a self-supporting adult.
^^^I don't think this scenario has ever happened anywhere on the planet. Correct me if I am wrong.
Bottom line: Unwanted pregnancy, regardless of how the pregnancy got started, is the reason for most abortions. Contraception use reduces unwanted pregnancy and therefore reduces the need for abortions. Banning abortion does not reduce unwanted pregnancies. It may not even reduce abortion that much, only make it more shady, more dangerous and more of a shameful secret due to its criminal nature. The fetuses will still die. Along with women and girls.
If people want fewer abortions, they should do everything possible to reduce unwanted pregnancies. That is the only rational policy-- and every country that has tried it has better outcomes than policies based on the fantasy world scenario.