I don't think it really matters that much, people need to figure themselves out one way or another. If he ever decides he's not bisexual, that's something for him to find out.

Seriously OP?

Would you question how he could know he’s attracted to girls?

I’m a bi person. I knew I was attracted to men and women by the time I hit puberty.

And no, it isn’t always a step on the way to coming out as gay or lesbian.

Why can’t gay (or bi) people know they are gay (or bi) until later.

My husband says that he knew from his earliest memories. When pushed for an age he will insist that he knew he was gay at 3.

Yes, the boy could know.

it always meant you will end up with a guy
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I thought things changed but looking at my kids friends it is absolutely still holding true