Concerning the separation of the genders, he preached that men should avoid looking at women other than their wives, mothers, sisters, etc. ("mahram"), much less trying to make their acquaintance. He opposed birth control and family planning as a "rebellion against the laws of nature", and a reflection of loss of faith in God—who is the planner of human population—and unnecessary because population growth leads to economic development. Mohammad Najatuallah Siddiqui writes, As to the argument that family planning enables better nourishment and education of children, Mawdudi refers to the beneficial effects of adversity and want on human character.