Why does the Buddha appear androgynous in some depictions? In quite a few depictions of the Buddha in artwork, he appears androgynous.

Does this represent something significant in terms of a Buddhist message or ideal, or is this just an artistic style?
It's an artistic style. The impression of androgyny is arising in the mind of the viewer (not necessarily every viewer), and part of its cause is our arbitrary cultural standard of how men and women should look.