Male and female symbols?

Does anyone have an idea of how one might plot male and female
symbols on a graph using R? Thanks!

You don't tell us your platform and the answer depends on the platform.

They are Unicode points U+2642 and U+2640.  So if your system supports it, 
something like text(x, y, "\u2642") will work, as will
points(x, y, pch="\u2642").

Alternatively, look at the Hershey fonts, which have these and many other 
symbols (not necessarily of publication-quality though).

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272866 (PA)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595