What do you think ?

In my opinion, he should have started talking to her about those things when she started to physically develop (12-15 typically); but 18 is better than never.

It would feel kinda weird to talk to your daughter about sex. That would be alot easier with the son. But you should have started way before 18. Like 10 even.

Both parents should be able to have a discussion about sex with their kids. My son is 10 and he asked me about sex. I told him, not too much physical detail, but I’d rather do it than him believe what the kids in school are saying. Or someone touch him in appropriately and he didn’t realize it was wrong. 🤷🏾‍♀️

My parents never spoke to me about sex. It was very taboo in my Catholic household.

Like others who have responded, I think 18 is way, way, way too old to have The Talk these days. I mean, I assume you're not a total psycho who has kept your daughter locked in the cellar for the last 18 years, so she will have picked up all sorts of stuff - correct, wrong and ridiculously stupid - from all sorts of sources by now. And, no matter what you might want to believe about her, she's very likely based some of her decisions on that information.

Our daughter is only just into her teens, and she's known the facts of life for years now. As far as I can recall, we gave her the first an age-appropriate sex-education book when she was around seven years old. Because we knew she found the subject cringy, we said, "Here's a book that explains some things you'll probably be curious about, either now or in the future. You don't have to read it and we're not going to test you on it or anything, but if anything confuses you, then you shouldn't be embarrassed to ask us about it." About three years later, we gave her another book about puberty and relationships that went into the nitty-gritty of sex in a bit more detail.

Fathers talking to daughters about sex is always going to awkward (and the same applies to mothers and sons), but I think one thing a father can usefully do is try to educate his daughter(s) about what goes on in the minds of boys and young men. Your daughter is most likely already very aware of the horn-dog nature of most male teens, so you don't really need to get into that. But there are other things, like how girls need to understand that boys simply aren't as empathetic as they are, they're generally really crap at reading non-verbal signals, and the best way to communicate with a teenage boy or young man is to whack him on the head with a metaphorical two-by-four.

as long as its a serious discussion about risks & consequences and not a show & tell then yeah its normal

and 18 is way too late for that shit anyway that ship sailed by then

Yeah if you don't make it weird it won't be weird

Seems kinda late to be having the talk.