It's crazy how radically different everyone's views are on this. Well, I guess not everyone, but more of the 1940's attitude than I would expect I guess. I was just debating this today because my 7 year old was like "Dad look at my penis, haha, it's sticking straight out!" and I just went "Har har, keep it in your pants buddy." and he just laughed and went back to playing a game. It did get me thinking about it though, and while at his age I think I would deflect with "We'll talk about it later" or something, I'm pretty much expecting that I'll be going into detail with him next year, or the year after. My main concern was that his brother is 5, and he's probably going to want to tell him right away, so I have to consider that.
That being said, they have seen me and their mom naked, and they know girls have a vagina and pee straight down, while boys have a penis and pee straight out. They know babies grow in a mommies tummy, and come out her vagina. And they know babies are half mom and half dad, although they have never asked how any of it happens.
But yeah, I'd say if anything I'm looking forward to being open and honest with them, hell, I'll probably give them advice when they are older. I will probably buy them some mild couples porn around 11 or 12? Tell them masterbation is fun, everyone does it, even animals do it, anyone who tells you they don't is a lier. I want them to be prepared, safe, and have somewhat realistic expectations though, and I don't think that's something you get when you rely on the internet and stories from friends.
I don't know, maybe its how blind I went into everything as a kid because my parents pretended sex was something you did to make a baby and nothing else, it was not talked about other than "here is how it works" on the most basic level. I just want my kids to have a relationship with me based on trust and understanding I guess, and I'll admit I'm more of a friend dad than a "manly" man dad or whatever. /shrug