There are numerous small details that give clues about what gender someone is.  Some o fthese include:

<ul>
<li>facial contrast &mdash;<a href="http://gajitz.com/holy-androgony-gender-illusion-contrast-attractiveness/"> Russell R, 2009, "A sex difference in facial contrast and its exaggeration by cosmetics" Perception 38(8) 1211 – 1219 </a>  (<a href="http://public.gettysburg.edu/~rrussell/Russell_2003.pdf">full paper</a>)
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