My post expressing skepticism about birth rate forecasts for 45 or 100 years in the future led me to think: What changes might substantially increase birth rates in the developed world?

Here's my candidate: A combination of (1) cheaper, less painful, and more reliable egg extraction and freezing, which would let 20-year-old women routinely bank eggs for the future, and (2) the invention of incubators that can safely grow a child from a fertilized egg to a live baby. It's of course impossible to be sure that development 2 will happen within the next 45 years, but I suspect that it will. Let's say for our purposes that it does. Why is this likely to substantially increase birth rates?

It seems to me that many couples have fewer children than they'd like, for several reasons. First, both the increase in women's educational and professional opportunities and changing sexual mores have led many women to marry later, and to have children later. They may still want to have 2, 3, or more children, but it becomes harder to do if you start in your mid-30s.

Second, pregnancy is hard work, especially if you also have one or two kids running around and contributing to your tiredness. Pregnancy and childbirth can also cause various health problems. Some women apparently really enjoy pregnancy and even childbirth, but I suspect that most don't. I doubt that this deters many would-be first-time mothers -- but it may deter some women who already have two kids, have experienced the unpleasantness of pregnancy, are older and thus more likely to find physical burdens more taxing, and feel less of a need to have that extra kid.

Third, I suspect that quite a few families might want to have another kid as their first batch gets older. Today, it's just not an option, at least without a great deal of work. (Adopting is of course always possible, but many people are reluctant to do that.) But if it becomes easy, I suspect a significant number of older couples may take advantage of it. Here I'm less certain, and of course as someone with two small kids I fully understand that many older couples may have no interest in going through all that again. Yet if even a substantial minority (say, 10%) do take advantage of new technology to do this, the birth rate may go up nontrivially.

So if age-related fertility decline stops being a problem, and the physical burden of pregnancy and childbirth is eliminated, two important deterrents to having more children would be eliminated. Naturally, there are plenty of other deterrents; technology won't make having children cost-free. But it will reduce the costs (I speak here mostly of nonfinancial costs) and thus increase the demand.

This is all guesswork on my part, and it may be skewed by the circles in which I travel. It would be interesting to see if there have been surveys that try to measure (however imperfectly) the extent to which people would have more children if the problems I describe were solved. Still, my suspicion is that this could easily drive up the birth rate by 0.2 or 0.3 per couple, or perhaps even more.

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