Readers, a mystery to solve.

Any sci-fi readers out there, I need your help please. I have a mystery I’ve been unable to solve.

I can’t tell you much, but I’ll tell you what I can.

In the early to mid 90’s I borrowed a book from the library, and little bits of it just stuck with me, but for the life of me I can remember the title or author of the book. No-one I have asked since, has ever recognised it.

So this book had a scientist/genetics expert in it, he and his wife had a child, and as far as I remember unknown to her he altered the child’s genes to make it super intelligent.

Continuing onwards said child is born, and around 10 months old (I think) starts suddenly talking in the supermarket saying things like coffee, and spaghetti.

I am hoping you can help me find the book again. I’d like to re-read it. Thankyou to all my wonderful readers.