Not to get into a flamewar or anything, but if you're trying to prevent abortion then voting for the R candidate isn't a sensible choice. Hand in hand with wishing to ban abortion, they generally are hostile to the very policies (free birth control, such as IUD, on demand) that are the most effective in preventing abortion. Colorado cut teen birth rate and teen abortion rate in half simply by offering free IUDs[1].
The thing with the two party system is that the real choice for voters happens in the primaries. This is the chance to swing the party in a different direction, since in the general election people will typically hold their nose and vote a straight ticket even if they don't like all the positions their candidate holds.
[1] https://www.colorado.gov/pacific/sites/default/files/PSD_Tit...
People over-reproducing is a strain on society. I'm not saying we should limit how many children folks can have, but there isn't any societal upside to 14 person families.
A robust sex ed curriculum, free contraceptives for everyone NQA, free abortions up to delivery. Fund social services adequately. One party is dying on the hill in an attempt to prevent these rational evidence based measures. I'd rather believe that gullible religious types are tricked into hating these things because it helps the capital class maintain a large uneducated and impoverished workforce. I realize that this may be wholly wrong.
On the other side of things..
If the birth rate declines too fast then entire generations will be raised to keep their ancestors alive, instead of doing other things like mining asteroids or creating new AI to better sell Facebook's new facehugger 3000 vr facemask with built in respirator.