"Birds do it, bees do it..." We are pretty clear on the reproductive process in nature, including OUR nature.
Now, anyway... but for much of human history, we might as well have truly believed in storks delivering babies. Everything from religion to lack of good microscopes got in the way.
Science journalist Edward Dolnick follows the progress of science toward getting a handle on how babies are made, in his book The Seeds of Life. The author joins us with an overview.