Am I the only one sitting here
wondering about the username "xtin?"
OP, I am going to preface this by saying that I can't imagine any of my kids "gender bending." All 3 of them are really focused on being a girl or boy even though they are all provided with a large variety of toys and dress up options. About the only thing I put my foot down on is flashy clothing or clothing I personally find immodest.
For some reason, reading this thread reminded me of how my DD would get into the car after a day of preK and cry to me because her teacher hurt her feelings. Once it was because DD hadn't drawn her letters right. DD told me her teacher told her she was doing it all wrong. Really, the teacher just showed her, "This is the way I like to do it." However, DD reinterpreted it for herself. Another time, the teacher didn't hear her tell her something because she just didn't speak up. And another time, she was upset because she got 3 gummi bears while the friend next to her got 4.
I think the connection I made was that there are a lot of things that teachers do/say that are completely reasonable that get twisted in their little minds and feelings. If we as parents make a big deal of it, then it makes it stick. If we just say, "I'm sure the teacher just wasn't counting those gummi bears. I'm sure she wasn't trying to make you feel bad." then we help our kids move on from their perceived slight. I think sometimes we have to help them see that not everything is directed right at them.
We don't know the context of the conversation that happened. We don't know if they were talking about various costumes and someone pointed out that Tink is a girl and the teacher agreed. (and last time I checked Tink was a girl!) We don't know if the teacher assumed your DS was trying his hand at humor and she reacted to it that way.
We also know that preschoolers and their obsessions are fleeting and what he wants to be this week may be different come next week. I know my 4yo has been vacillating between being a "blue dog with a green tail" and a "teenager dragon."
I am thinking that if you overdo it, you'll make it a bigger deal than it is. As well, I would be careful telling him that he could be anything he wants unless you really are willing to let him. I can tell you right now that I wouldn't let any of my children dress in some of the commercial constumes I see because they are flat out trampish or creepy. Obviously, Tink doesn't quite fall into that category (unless you are looking at adult costumes).
Sheesh! I sound bossy. I am not meaning to be. It's just how I think about things.