Just financial arguments against, ... but to be honest it's kinda hard to manage. I'm the tail end of a baby boom, which has some benefits, my age group, being a large demographic have had the market shaped around us somewhat, there's lots of products and services aimed at us.
Downside is that there are fewer younger people, so those of my age who haven't prospered are going to have a lean time on a state pension.
So sure, birth control, ie, the older people in the baby boom deciding to work for longer before having kids has caused this disparity, but it also made the demographic we enjoy.
I don't think govts can react fast enough to offer incentives to keep people breeding and not using birth control to maintain a static population. I think they offer too many incentives to breed in the first place, and that places strain on resources.