According to Britain's Human Fertilisation and Embryology Authority, if your child or children were conceived as a result of donor assisted conception, telling them about their origins at the right time, doesn't have to be difficult. This is especially true if you talk to your child early about their donor conceived origins.
Evidence from the experience of adoption, and well-studied donor-conceived people, suggest that its best for donor conceived people be told from the earliest age possible. People who find out later in life, may experience emotional damage, and damage to their relationships with their families. However, if because of circumstances or by choice, that have led parents to tell their child later in life, can still be done well with the right guidance.
Being open and honest is the best policy. Families who have secrets undermine trust that leads to conflicts and can feel that their parents were ashamed of them or how they were conceived. If parents are open about how their child was conceived, there is no reason they should feel any different from any other child. If donation has been part of the family story for as long as the child can remember, their genetic origins needn't be an issue. Some donor-conceived children are likely to want to know more about their donor, while others won't be particularly interested at all.