Aude Lapinte, division Enquêtes et études démographiques, Insee
In 2011 in Metropolitan France, 1.5 million children aged under 18 lived in 720,000 blended families, that is, a family in which not all the children are those of the current couple. 940,000 of them live with a parent and a stepparent, most commonly with their mother and a stepfather. The remaining 530,000 live with both their parents but share their lives with half-brothers or half-sisters. Within blended families the youngest children are, logically, those of the current couple: 85% of children aged under 4 live with both their parents, against 10% among those aged 15 or over. When blended families form, children may also live part of the time with their other parent. Among children living mainly with a stepparent, three out of ten also live regularly with the other parent. Additionally, 140,000 children who live with both their parents in a traditional family share their dwelling for short periods of time with half-brothers and half-sisters who mainly live elsewhere.