Your son is fortunate indeed to have parents who aren’t quick to over-react. Often it is a parent’s reaction that makes something simple into a big deal.
You’re right. A 4-year-old doesn’t yet know all the social rules, although he’s already accepted some of the cultural definitions of what are “girl things” vs. “boy things.” My best suggestion is that you out-and-out ask him what he likes about having your things – as matter of factly as you can. Turn the conversation to a short explanation that underwear is a private thing that boys and girls don’t share. Keep it lighthearted. Joke with him about how silly you would look trying on his shorts.
It’s important to remember in situations like this that young children explore their world with all of their senses. When confronted with something new, they handle it, smell it, and even taste it. As we get older, we tend to drop off smelling and tasting novel things and even limit how much we go around feeling textures. Adults rely pretty much on sight and hearing to explore. One possibility is that your son simply likes how your underwear feels and he doesn’t have anything as soft, or silky, or pretty. If that’s the case, perhaps the two of you could look around the house for something else that feels nice.
My other guess is that having your underwear is about wanting to have a bit of you with him when he is anxious. If he is using your panties partly for security, see if there is something else of yours that he would like to have close to him at night. If I’m right, an old T-shirt might do. One of my kids took an old pajama top of mine to bed with him for about a year – his variation on the blanket lots of kids get attached to.
I think it is quite normal for both boys and girls to want to be close to their moms when an interloper in the form of a new sibling comes into the house. Your son was old enough when the baby was born to remember when he had your exclusive attention and time. Sharing is really, really hard. Somehow being “big” isn’t always what it’s cracked up to be. Do give him strokes for being a “big brother,” of course. But I hope you will also continue to give him some time each day when he can be cuddled and tickled and held while baby plays or naps.
I wish you well.
This article has been updated from the original version, which was originally published here on March 28, 2010.