All the comments are about having babies but as the article points out the actual proximate reason the US population is declining right now is the immigration enforcement approach taken by the Trump administration. Fewer people are coming the the US (including legally), and more people (including legal residents) are being deported or are leaving, and as a result there is net outflow of people from the country. The situation will only worsen with the incipient war on H1B and other visas.