Mothers who give birth using donor eggs do not have the same connection with their babies as women who use their own eggs, a new study suggests.

Scientists at Cambridge University found that women who do not have a genetic connection with their offspring show “subtle yet meaningful” differences in how they interact.

Their observations showed that donor mothers made slightly less eye contact with their babies and responded less to their games.

The researchers believe the differences may be explained by an awareness on the part of the mother that they are not genetically linked to their child, or because they typically arrive at parenthood later in life.