According to a CDC report today, the number of babies born per female (ages 15 to 44) in the U.S. is the lowest ever.

That rate is known as the general fertility rate (even though it measures reproduction, not the capacity for reproduction—fertility as it’s used colloquially). It has been tracked since 1909, and it has dropped more than 10 percent since 2007.

Beyond the social implications of this relative decline in baby production, it may be the best recent news for human health at a population level, as Earth is unsustainably full of humans. That’s tough to say without sounding “evil,” I’m told, but it’s a question of math. There is not enough space to house and feed everyone. Population growth has us on course for catastrophic famine and war that result from overpopulating a planet that is growing ever less habitable.

Even while the rate of baby production is at an all-time low, the U.S. population is so large that the absolute number of babies is greater than it was even just a decade ago. And while the fertility rate among women under age 30 is decreasing, pregnancies among women between 30 and 44 still are going up, partly due to IVF and other reproductive technology. The national population is still growing rapidly, too; CDC projects that by 2060, the number will jump from 319 million to 417 million.