The problem with the GOP's newfound enthusiasm for IVF is that it contradicts other positions the party has taken to please pro-life voters. In the last Congress, more than 160 House Republicans, including Johnson, cosponsored H.R. 1011, the "Life at Conception Act," which extends 14th Amendment protections to include "preborn human person(s)."

Republicans have also marched in lockstep to oppose the Right to Contraception Act introduced by Democrats because it would have included methods, such as IUDs and the morning-after pill, that some consider abortifacients. It's hard to square support for IVF, which, as practiced in the United States, nearly always entails the loss of fertilized eggs, with opposition to Plan B because it may result in the loss of a fertilized egg.

Maybe the lesson here is that doctrinaire approaches to these matters are not right. Life is full of trade-offs. Johnson is right that IVF has been a blessing for millions, and that includes many people who think of themselves as pro-life. For every 100 Americans born today, between one and two will have been conceived through IVF. By 2015, more than 1 million Americans were born as a result of IVF or similar technologies. For people diagnosed with cancer, IVF can preserve their fertility until after they have completed chemotherapy. For couples who are carriers of genetic diseases like cystic fibrosis, sickle cell anemia, Tay-Sachs and more than 400 other disorders, IVF can allow embryos to be tested before transfer to ensure that the disease is not present. Is that a pro-life gift to the world? Millions of Americans think it is — even though the procedure involves the loss of embryonic human life. It isn't a failing to recognize that these matters are murky and sometimes we do act on moral instinct more than on bright lines.

It is possible to approach the process ethically and even reverently. Some couples make decisions in advance about how to handle the question of "excess" embryos that have not been transferred after IVF treatment (only a fraction of transfers result in implantation and pregnancy). Some place frozen embryos for adoption. Others have larger families than they might have originally intended because they regard the frozen embryos as their children.

It's difficult for a political party to escape its brand. Just as Democrats will have difficulty convincing voters they aren't soft on illegal immigration, Republicans won't easily escape the association with hard-line abortion positions, including opposition to certain kinds of contraception. The personhood bills that four states have enacted and a dozen others are considering draw a harsh line on matters like IVF, which does entail making life-and-death decisions about frozen embryos. The voters may force Republicans to reconsider their blanket support for personhood bills. Perhaps pro-natalism is the pro-life position the GOP needs.