Of course he doesn't. If you support unrestricted abortion - and, in the case of China, forced sterilization - you wouldn't have a problem with forcing parents to limit their families.
Mark Hemingway at Weekly Standard:
Good news, reproductive rights advocates and neo-Malthusian environmentalists! Vice President Joe Biden has no problem with the government forcibly sterilizing people and compelling abortions. From his remarks at Sichuan University in Chengdu, China yesterday discussing the U.S. debt.
It's perfectly understandable that you let the government tell you how many children you could have if that helps get the debt under control, right? Republicans better get together and compromise on the president's grand bargain sometime soon, or else.
If government can force you to buy insurance to keep costs down, it can force you to limit your family for the same reason.
That's not a "slippery slope." It's a fall of a cliff.