My idea of how a female Sonic would look, which is likely to be different than how most other people draw a female Sonic. Here are my reasoning for her physical traits:
:bulletblue: No additional clothing mainly because I feel it is unnecessary considering Minnie Mouse can get away being topless. :bulletblue: Shorter head quills because female animals usually don't have the long flowing hair/vibrant feathers as their male counterparts. Look up male and female peacocks and tell me which one looks more impressive. Actually correction; peacocks and peahens. :bulletblue: Small breasts because she's very lean and athletic, making huge knockers inconvenient. :bulletblue: Skinny longer tail — Thinner quill makeup, longer because I felt like it. :bulletblue: The extra "quill fluff" at the bottom row of her head quills — aesthetics mostly. You can also view this as more "cutting edge(s)". :bulletblue: Single long eyelashes — to differentiate his already canon girly eyelashes from the male version.
Unfortunately I drew this on a small canvas :( derp. Anyway feel free to comment whatever. Let me know if you like to see more gender bender art. I plan to do Shadow and (revamp) Silver female versions =P