Lol. Yes, nice to know people have read my posts.
In short, you only need 1 nursery. Having more doesn't increase the birth rate. More will serve like a medical center (for kids only), but it is only as effective as a single unupgraded medical center would be, which takes an equal number of workers and scientists.
You get more out of building a new medical center (since it helps prevent deaths in all 3 population components) than you do out of a second nursery. There is no point to building a second nursery.