Less than 5 minutes in, just watch the opening.
"Conservatives, if you think population needs to be at replacement level, and someone goes out there and gets sterilized, it is incumbent on you to have the two extra kids that family should have had. And people turn around and say, 'well Tim, you don't have any kids!' And yeah, but look, when you come to me and talk about this stuff, I take the libertarian perspective of 'if you don't want them to do this, I don't know what to tell you'."
The libertarian position is not "I don't know", Tim. Libertarians have positions on a whole host of issues. You cannot claim complete apathy of a situation and state that it is because you are libertarian.
Ignoring the fact that the doctor has sworn an oath to do no harm, because Tim acknowledges that the doctor doesn't have to provide a service just because someone wants it, so he's right on that issue already, there is a broader point to make here. Our society is getting older, and living longer. We have all these great medical advancements that let people live past 100. And yet, when all these people leave the work force and spend 30+ years in retirement, someone is going to have to fund their social safety net. Someone is going to have to be paying for their insurance. And it can't be the 30+ year olds, because insurance needs payments without withdrawals to function, and 30+ year olds have back problems, maternity, some of them start to have cancer, you can't have middle-aged people paying the insurance bills for old people. It has to be young people.
If we want Social Security and Medicare to continue to function at all, we need workers. If we want new houses to be built, if we want crops to be picked, if we want cars to get washed and store shelves to get stocked, we need workers. Society depends on replacement. It is not libertarian to say "well, fuck it, humanity is unsustainable so let's just kick back and wait for all the problems we caused to pile up and deal with them then".