Pure discussion

Ok so Ive only read half of Pure so no spoilers please.

I just had a question about relationships between half bloods and pures. I know that its forbidden for them to have relationships but is it ever mentioned in the first book about any pures and half bloods having children together? I dont really remember much about book 1 because I read it so long ago but it was just something that Laadan said about Alex's father that got me thinking whether or not he was really a mortal. If Im on the right track or not please dont tell me though. I want to find out for myself if my theory is right.

you'll learn later on what the result is of a pure and half blood - it doesn't happen often, and if it does and results in a baby -there's something specific that happens.

Ok. Thanks. I just didnt remember if something was said in the first book.