Prima facie, the evidence seems obvious: removal of dysgenic traits leads to the lowered frequency of those traits. But abortion doesn't just target the genetically undesirable. It seems to be a solution for the inconvenient as well. Take black Americans, a demographic which aborts at a rate over twice that of whites. These abortions aren't a random sample of the black population. There is a self-selection bias by black women, usually those who feel the pregnancy will interfere with future plans for an education or career. Isn't it plausible those who choose abortion might be of higher genetic stock on average?