James Taranto writes about The Roe Effect:
It is a statement of fact, not a moral judgment, to observe that every pregnancy aborted today results in one fewer eligible voter 18 years from now. More than 40 million legal abortions have occurred in the United States since 1973, and these are not randomly distributed across the population. Black women, for example, have a higher abortion ratio (percentage of pregnancies aborted) than Hispanic women, whose abortion ratio in turn is higher than that of non-Hispanic whites. Since blacks vote Democratic in far greater proportions than Hispanics, and whites are more Republican than Hispanics or blacks, ethnic disparities in abortion ratios would be sufficient to give the GOP a significant boost–surely enough to account for George W. Bush’s razor-thin Florida victory in 2000.
The Roe effect, however, refers specifically to the nexus between the practice of abortion and the politics of abortion. It seems self-evident that pro-choice women are more likely to have abortions than pro-life ones, and common sense suggests that children tend to gravitate toward their parents’ values. This would seem to ensure that Americans born after Roe v. Wade have a greater propensity to vote for the pro-life party–that is, Republican–than they otherwise would have. . . .
Critics of the Roe effect hypothesis point out that abortion does not necessarily diminish a woman’s lifetime fertility. A woman may, for example, have an abortion while in college, but later marry and bear children–children she might not have had, had she been forced to carry her collegiate pregnancy to term. Yet it is not clear how much this might mitigate the Roe effect. Some women do abort their final pregnancy, and delayed childbearing is one manifestation of the Roe effect. If a woman has a child at, say, age 30 rather than 20, one additional census passes before the child counts toward his state’s congressional and electoral college apportionment, and two or three presidential elections pass before he reaches voting age. The compounding element applies here as well; if a woman has a daughter at 30 rather than 20, the daughter reaches childbearing age a decade later than she otherwise would have. Moreover, attitudes about abortion and politics are subject to change with age and experience, and usually in a conservative direction. Thus, some women who delay childbearing contribute to the Roe effect on both ends: by having abortions when they are young, single, and pro-choice, and by bearing children when they are older, married, and pro-life.
Read the rest at the link above.