Correct, but the point in the pregnancy where abortions are so considered has varied a bit.  It is very recent that conception was a marker and it can and should change again.

Until gastrulation, the male dna is silent in development.  Gastrulation is when it starts to work.  Until then, its mom's show.  After gastrulation, abortion is killing a soul, however because of miscarriage, the law cannot protect it except with economic means.