Three Partners, One plan

The Talmud explains that that there are three partners involved in the creation of a child – the father, the mother, and G-d.

Of the three partners, it is G-d who knows the future as well as the present, with all of its circumstances and details. He is also the one who best knows the perfect time for the child, the mother, and the father.

So why not let G-d do the planning?