The sad fact is that nearly a quarter of all pregnancies in the US end in abortion. Imagine the numbers of playful, happy children never had a chance to be, due to abortion.
We are doing better than some other countries, though, look at Russia!
How to make it unnecessary? Well, that's easy. Just keep all pants zipped until after marriage, and don't marry until you're ready to have children.
Easier said than done, you say? Yes, yes it is, but it is the only way to eliminate the need for abortions entirely. What we need to do is to work to discourage abortion as much as possible: Promote safe sex, promote adoption, promote parenthood, and make it easier for young mothers and fathers to raise children through access to day care and child health programs.
Not to mention demonstrating to the youth a faithful monogamous relationship.
Nothing other than what I just said will end abortion, not even an outright ban, but that 1/4 figure is way to high.