My 4-year-old son, Emmett, swallows a spoonful of cereal and asks me if I know what a gentleman is. Surprised, I tell him I have some idea; then I ask what the word means to him.

“A gentleman lets girls go first,” he says, explaining that every day at naptime all the girls go to the bathroom before the boys.

His explanation, along with the quiet solemnity with which he delivers it, is completely endearing and yet it makes my heart ache. This adorable little boy, who is only beginning to learn the ways of the world, just got his first lesson in sexism — and from a teacher who, I don’t doubt, believes she’s doing something wonderful for womankind.

She isn’t the only one.

Start to complain about your preschooler adopting gentlemanly behavior and you quickly discover how out of step you are with the rest of the world. Almost everyone I mention it to thinks it’s lovely and sweet. What’s the harm in teaching little boys to respect little girls?

The implication, of course, is that I’m overreacting, and as a parent, I’ll admit to being prone to the occasional bout of hypersensitivity. For months, I grumbled that the inappropriately breathy tone of Cinderella on Emmett’s LeapFrog Princess laptop was warping a generation of impressionable young minds.

But I don’t think it’s an overreaction to resent the fact that your son is being given an extra set of rules to follow simply because he’s a boy. His behavior, already constrained by a series of societal norms, now has additional restrictions. Worse than that, he’s actively being taught to treat girls differently, something I thought we all agreed to stop doing, like, three decades ago. That the concept of selective privilege has been introduced in preschool of all places — the inner sanctum of fair play, the high temple of taking turns — is mind-boggling to me. How can you preach the ethos of sharing at the dramatic play center and ignore it 20 feet away at the toilet?

Yet as much as this double standard offends me as a mom, it’s nothing compared with how much it infuriates me as a feminist. Forty years after the tender, sweet, young thing in “Free to Be You and Me” gets eaten by a pack of hungry tigers after asserting that ladies should go first, we are still insisting on empty courtesies that instill in women a sense of entitlement for meaningless things. Many women see gallantry as one of the benefits of their sex; I see it as one of its consolations.

Letting girls use the bathroom first isn’t a show of respect. It is, rather, the first brick in the super high pedestal that allows men to exalt women out of sight. A true show of respect is paying us equally for the same work, not 77 cents on the dollar, which is the current average. That’s the world I want my son to live in and I seriously doubt it will ever happen as long as women believe men should hold the door open for them.

Global economic considerations aside, the real tragedy is that these girls aren’t being taught the fine art of yielding to others. Nobody is giving them the opportunity to be gallant. Instead, these fabulous little creatures, who absorb everything joyfully and tear through barriers gleefully, are being fitted for the same old corset. The stays are a little looser but the whalebone is just as rigid.

And this is why my heart aches when I listen to Emmett proudly explain what a gentleman is — because what he’s actually so proud of is his part in perpetuating millenniums of sexism.

So while he finishes his bowl of cereal, I tell him that I think a gentleman lets other people go first. If two boys reach the top of the slide at the same time, a gentleman lets the other one go first. Furthermore, I say, it would be very nice if his teacher decided to alternate on a daily basis who uses the bathroom first at naptime. The girls, I assure him, wouldn’t mind waiting a few extra minutes and it would give them a chance to feel gentlemanly. But the concept of a gentlemanly girl is beyond him and he shakes his head.

It’s churlish to argue, so I let it go, and when, a few hours later in the park, I see him grab his soccer ball from a girl his own age, I feel a ridiculous rush of relief at his ungentlemanly behavior. Then I cross the field to remind him yet again how to share.