Horizon Season 31, Episode 17
Airs: 9:00pm - 9:50pm on BBC TWO
Investigates the theory put forward by biologist David Haig, who suggests that, far from being a period of physical harmony for mother and baby, during pregnancy the two are engaged in a struggle through the placenta to control available resources, such as oxygen and sugar. While the baby's genes are trying to promote growth, the mother's genes are trying to restrict the draining effect.