AITA for calling my biracial children my "dumplings"?

Title pretty much says it all. I'm white and from the Midwest and my wife is American-Chinese from the Northeast. We have two boys who are gorgeous balls of snot and charm.

When my wife was pregnant with our first, I started telling her that she had a dumpling in the oven (instead of a bun). Yes, I'm aware of how lame this joke is. But she liked it and I liked it and it just sort of stuck even after the little tyrants clawed their way out.

The other day at work I was showing pictures to my coworker (yeah...I'm that guy...) And I referred to them as "my little dumplings." My coworker told me that it was offensive and essentially said that I'm going to fuck my children up by making them hyper-aware of their race.

We actually had a pretty decent conversation about it - she asked me if I would call them dumplings if they were white, which I wouldn't because it wouldn't make sense because the entire joke started because my wife is Chinese - but I still maintain that I'm not an asshole here. The only thing that really irked me about the conversation was that she said it'd be fine if my wife called them dumpling, but not me because I'm white.

Except for that last part, I understand where she's coming from, but honestly, I don't think it's that big of a deal. They're my kids too and my wife doesn't have a problem with it. We've had a lot of open conversations about race because our backgrounds are so different, and we've decided that we shouldn't shy away from acknowledging the differences between us or the unfairness because of it. At the same time though, our kids are biracial so although we should make them aware of what might be waiting for them out there, we should try our best to not make race a huge issue for them.

Also, dumpling is only one of the names I call them. I also call them monsters, brats, cuties, and (to my wife in private) fucking assholes.

So Reddit, AITA? I love the little guys to death and I'm doing my best not to fuck them up too badly.