Except it's not. ^^
And that's not even my opinion, it's something that's examined by scientists. Psychologists everywhere are contributing high suicide rates and a spark in anxiety and depression to kids being DENIED these conversations.
To give an example that fits the topic: many trans youth (and older people who are already comfortable in their gender identity) keep observing that even body dysphoria often doesn't necessarily come from themselves—but from the people around them and society's expectations about male and female people. Not to mention society's trouble to just accept that there simply aren't only two genders, but a myriad of different gender experiences that just somehow fall under the male/female umbrella. Or they don't, and you are non-binary. Or genderqueer. Or, if you're a Native American, you can be two-spirited. These things didn't pop up only recently, they can be traced back through human history for aeons.
The thing is: kids sense when they are different from the heteronormative society. They sense it very early, most of them anyway. The first time I kinda noticed that something was off within me? I didn't have the words to express that I had a crush on a girl friend of mine. I didn't have the words because it was simply a non-existent reality in my immediate surroundings. Neither the media nor my family or friends offered me any representation that could have explained to me what I was feeling when I had my friend's fragrance around me.
Had I been given the words, had I been given the conversation that girls don't have to like boys? I would've known what to make of these feelings. But because no one told me that this even EXISTED, I didn't realize that I could, in fact, like girls/women until I was over 20 years old, resulting in major anxiety and identity problems.
Love between kids isn't inherently sexual. When I had my first crush (on a boy back then), I was five. Five! It's not education about other forms of love that sexualizes kids. It's the heteronormative society that sexualizes anything that's not heterosexual to the point where two girls or boys holding hands is seen as impure. It isn't. It's just adults projecting their homophobia on these poor kids.
Give kids the words for what they can potentially feel, and there's no problem. There's no reason to make it sexual. "Boys can like boys, and girls can like girls; and sometimes, you don't have to be either and can like both" (or, well, anyone). What is sexual about that? Nothing. Nothing at all.
Yes, this! Education is pivotal to help kids understand what is possible, and to give them the words they need to express what makes them different from other children around them. Because, yeah, straight cis people are still the majority! But that doesn't mean we have to make them the standard. We're all right just the way we are. o/
Now, considering gender, @tired_programmer...
I think it's hard for us (mostly) cis people to try and describe what it might feel like not to be the gender that was assigned to you at birth. Since it's not always linked to gender/body dysphoria (many trans people just feel gender euphoria, meaning that elated feeling when someone genders them in their preferred pronouns and the like ^^), there's... not really a rule, I suppose.
So, since I would say I'm cis-...ish, I don't think that I can talk about that feeling. I've been following a lot of trans people on twitter, learning from them, accepting that gender is a social construct and women can have penises and so on... So maybe, by doing so (and/or reading blogs), there's a possibility that you could come near that feeling? I'd totally recommend listening/reading a lot, though!
By the way: even the term "biological sex" is being discussed by scholars by now. After all, if a penis doesn't make a man, and a vagina doesn't make a woman (also, don't forget intersex people): then what, exactly is the use in still assigning a gender to these organs at all? You know? It's basically just guesswork when a kid is born. xD
Gender is such a complex and beautiful thing when we let it develop freely within ourselves, and I just hope society as a whole acknowledges that in the next years or decades at the latest. ️