I've been reading through this thread over the last few days, thinking on how to respond ...
After the initial surprise, my parents have been supportive. Not only with wearing the kilt, but making my own kilts, sporrans, and belts (mother is a sewer and father is a do-it-yourself-er).

Brother #1 has worn kilts a couple times, and understands the appeal versus pants, but finds pants more practical for his everyday use. Also, he has concerns about ... er, accidentally answering the "Question."
Brother #2 would wear a kilt himself, but he's too concerned with what others think IMHO.
Both of them are fine with me wearing the kilt.

The only family who would be a problem (if his opinion mattered at all to any of us) would be my mother's brother. If he knows an ounce about something, he knows everything about it, and what he knows is the indisputable, undeniable truth. So there's only one Robertson tartan, which wasn't the one I was wearing (Hunting Robertson) and doesn't have any red in it.
And there was the "I worked all my life to be called a Mister, and I wouldn't be comfortable wearing a kilt" ramble.
He does have a saving grace - putting up with his ignorance with civility gives me practice for when I encounter unrelated idjits.