Many people hold that procreation is morally obligatory; one ought to bring children into existence because they benefit by being brought into existence. Often this line of thinking stems from the notion that procreation is intrinsically valuable; procreation should be pursued for its own sake. Other philosophers hold procreation is immoral because of the great harm it causes as a result of climate change, overpopulation, mental illness, and so forth. If current population growth continues, there will be an ever-shrinking supply of fresh water and food, leading to the suffering of future generations.