Reproduction bonuses, when setting up your race characteristics at the start of the game, are CHEAP.
If nothing else, reduce your Tolerance to 91%, then use those points to boost Reproduction by 9%, and you will enjoy a net increase in population growth of 7%, ABSOLUTE.
There may be some limit, drawback, or hidden catch to this that I just haven't noted yet, but I'll leave that to you smart college boys to figure out
