Cities 'are like giant contraceptives'

clipped from www.telegraph.co.uk Cities act like giant contraceptives and could help curb the Earth's explosive population growth that drives climate change, according to two studies. Rather than following the usual evolutionary line that individuals with more resources have more offspring, something different now happens as a result: parents are putting more resources into each child so they can compete with their peers, and this leads parents to have fewer children, she says in the journal Science. Meanwhile another study in the journal Science from Iceland suggests that the worldwide trend towards urbanisation could slow population growth because it offers a wider choice of potential partners. The reason is that married cousins have more children than do parents with closer or more distant relationships.