Research with young adult twins

Daan and Dirk are part of the 65% of twins that are dizygotic. This means not just one, but multiple eggs were fertilized at the same time. Dizygotic siblings are as genetically alike as their other brothers and sisters and share half of their genetic material. Behaviour is determined in part by genes, and in part by your surroundings. But what exactly is the ratio? 25 years ago the Netherlands Twin Register was founded to investigate this.

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