In the first year of life, the primary task is to learn trust, she says. And babies learn to trust people in the same way any of us do - by forming caring, stable bonds. But Dr Michael Humphery says the girls will probably suffer no long-term effects if the issue of their parentage is resolved quickly, and in their best interests. It's what happens between the ages of six months and two years that makes a lasting impact. In the meantime, the temporary foster parents can be expected to provide the twins with the best possible care, he says.
Twins can also form their own special world together.
It's possible that they can be sufficient to each other not to need to bond with anyone else. Prince's 80th birthday Links to more UK stories are at the foot of the page.