Booktalking "Jacob's New Dress" by Sarah & Ian Hoffman
Jacob wants to dress up like the girls do—the boy likes fashion. His friend Emily understands. Jacob makes his own dress, and he offers to do the same for Emily. His mother thinks that there are many ways to be a boy, and his teacher Mrs. Wilson explains that Jacob wears dresses because he feels comfortable in them. Jacob wants to be a princess, and he dressed up as a witch with a black dress for Halloween.
However, Christopher admonishes him to stop wearing girly clothing, and relentlessly teases him about his chosen attire.
Jacob's New Dress by Sarah and Ian Hoffman, 2014
I think that it is perfectly fine for boys to wear dresses, and some of them are lovely.