One can do all sorts of philosophising around this and come to a dozen different conclusions. What is noticeable is that anti-natalism crops up again and again as a hallmark of decadent societies, going hand in hand with the desire of the wealthy and powerful to extend their own lives as far as possible.
Population control, to be effective, must start at the other end. Do not reduce the birth-rate, lower the life expectancy. Palliative care only for the over-70s. Legal euthanasia. Removal of the current legal and social disapproval of tobacco, alcohol, fat and sugar. As things stand, the devedoped nations are having too few children while becoming overloaded wth the elderly. The assurance of a long, safe life causes people to delay having children into their 30s or even 40s, when any medical professionla will tell you that the best time for it, physically, is the late teend and 20s.
As to the old, don't fall for the hype. You can be a non-smoking, alcohol-free, decaffeinated vegetarian who runs three miles every day, does their mindfulness and yoga, dutifully drinks their however many litres of bottled water and applies all the required pills and potions. Knock yourself out. But by your 60s you'll be the same as me:- everything hurts and what doesn't hurt doesn't work. The natural lifespan of a human is around 40 years, after which it all goes downhill, regardless. When I was a kid, you married in your 20s and had two or three kids in quick succession. Then if you were a man you either died in your late 50s or early 60s, or died within a year or retirement at 65. Women got into their early 70s. Nobody had heard of dementia and, by and large most peole died while living independently in their own homes, not sitting vacant, drooling and incontinent in care homes, costing billions in care that could be spent on education.