It's the boys' turn. After millennia during which women have had to take most of the responsibility for family planning, a new, easy, and inexpensive injection could get men into the game. That would be a nice change of pace for couples in industrialized countries. But in developing nations -- where an inability to control fertility leads to serious health problems for women, financial burdens on poor families, and excessive exploitation of natural resources -- it could make a world of difference. That is, if pharmaceutical companies don't thwart the procedure's spread. Audrey Schulman gets the inside scoop on the latest alternative to the Pill -- only in Grist Magazine.