Women’s sexual desire is heightened if they are near breast-feeding mothers, a new study has found.

They appear to be turned on by a chemical odour from the mothers, and possibly their infants, say researchers.

Scientists think the substance could be a pheromone that evolved to stimulate reproduction at the right time.

Previous studies suggest that women living in early societies tended to have children when food was plentiful.

The pheromone would have helped encourage other women to reproduce when circumstances were good.