Breadcrumb: Why the male children?

In Ex. 1:16, Pharaoh commands the Hebrew midwives to kill all the male children of the Hebrews, but to allow the female ones to live. This seems odd, given that Pharaoh's motivation is that the Hebrews are too numerous and too powerful. After all, if one man is allowed to slip through, he could impregnate many of the Hebrew women, but the opposite is not true. If Pharaoh wanted to decrease the numbers of the Hebrews, he would have been better off killing the women. On the other hand, women aren't as good at lifting heavy bricks to build cities like Pithom and Raamses (Ex. 1:11) and presumably don't fight in armies. So Pharaoh dealt with his immediate problem (Hebrew warriors rising up against him) at the expense of the long-term one (too many Hebrews).