He didn’t say that teens need to step it up. He said that people are waiting longer to have kids, and at that point they are then having fewer children than are necessary to sustain the population, because of how long they waited. He then also said, interestingly for Fox News, that obesity rates, low-quality diets, and overconsumption of processed foods, and, I think, forever chemicals and microplastics, are all contributing to lower rates of successful pregnancy among people who are breeding at older ages.