When Liz's son Peter was five he asked: "Mammy, why does light travel at the speed of light?"

She was stunned and didn't have an answer for him. But she is used to being asked "way out questions". It is the little things like this, she explains, that she had noticed were different about Peter who is now 12, and Angela (16).

Both children are involved in the Irish Centre for Talented Youth in DCU.

"We were very very lucky in the sense that the school that they went to that the teacher was clued in and said that Angela was bright and needed a bit of stimulus." Angela was seven when her teacher brought this to her parents' attention and went on to attend a local Explorer club. Following that she applied to the ICTY and passed the assessment test, which allowed her to attend the Saturday classes and summer school.

"When you have your first child you are probably not inclined to think they are any different really, even though her language would have been quite advanced for her age. You don't think they are any different, just when the teacher did point it out, we said we'd better run with it."

Liz did notice that Angela was good at working things out for herself.

Another noticeable trait was that the children have extra sensitivity. "I remember when Angela was around seven or eight and she was crying and she said: `Mammy, I don't think like other children.' "

The children know that they are different, she explains, but not in a precocious sense.

"They are still children, whereas mentally they could be two or three years ahead of themselves. There is an emotional conflict there. They can see that they don't think like other children and they feel that they don't fit in and that is a difficulty that a lot of children, I think, at this level have." Coping with that as a parent, Liz says, is difficult - it's difficult to see them stand back and reflect like an adult. "They do reflect an awful lot."

Liz knows that some advanced children come across as precocious. She believes she has been lucky with her two; they're reasonably well balanced. "Some children might come across as knowalls. It's just they way their minds think - they just answer the question. Then of course they get the bullying. Things can be set in motion - teacher's pet know-all. That's not the way they are, it's just the way their minds think."

Both Peter and Angela attended a Montessori school, so Liz believes that they are lucky in that sense, because bullying was not an issue in the school. Some children can be disruptive, but this can be because they are always seeking answers. Because they think at a different level they can also become isolated.

Liz says that one of her children is more arts orientated and the other is more science minded. She doesn't like discussing IQ. "People are inclined to look at intelligence as logic-based, good at maths, good at science," she says.

"Really when you look at these children they are very philosophical. They really think about things very deeply and they are very sensitive."

They are still people, behind it all, with emotional and social needs. Liz believes that society can't really cope with it and presume that talented children are lucky because they can do well at exams. "There's a little more to it than that."

Involvement in ICTY has given her children a forum where they realise they are really not that different. They have a social network of like-minded children from around the country, which they can meet, e-mail and keep in touch with. They help one another.

"It gives them reassurance, it gives them confidence, it builds up their self-esteem, they don't feel so different, which they may do."

Names have been changed.