According to a recent study if you're older than your siblings you're likely to be smarter than them. Research by a team from Leipzig University in Germany claims to show each child after the first is slightly less bright as they have to share parents. Scientists also suggest that having your parents' undivided attention means you end up learning more which benefits the eldest child. However in a two-child family the eldest won't necessarily dominate. They have a six in ten chance of a higher IQ so their younger relatives still have a strong chance of overtaking them. As well
