Though the message may have gotten lost in the flood of news out of Washington, President Trump and his leadership team have made a priority of getting Americans to have more babies. The most recent data show that the average U.S. woman will give birth 1.62 times over her lifetime—far below the replacement level of 2.1. But the policies the pronatalist White House is considering vary wildly in their efficacy.

At the 2023 Conservative Political Action Conference, Mr. Trump said: “We will support baby booms, and we will support baby bonuses”—paying parents for having children—“for a new baby boom.” Vice President JD Vance has taken up the cry, saying in January that we need “more babies in the United States of America.” Officials are soliciting advice from experts on pronatalist options. Some involve subsidies for births. This would be a mistake. The better idea is to make in vitro fertilization affordable and accessible. ...

Baby bonuses have proved costly and ineffective. Children are expensive. From time to time, the U.S. Department of Agriculture estimates the cost of raising a child. The USDA’s latest report, published in 2017, suggests it costs on average about $234,000 for a middle-class married couple. This estimate is based on spending data and includes housing, food, clothing, healthcare and other costs between birth and age 17.

That leaves a lot out, including direct expenses after 17, the largest of which for many families is college. Higher education on its own costs on average $38,000 a year, or just over $150,000 for a four-year degree.