Hey Julie,
In SAS 9.2, this is very simple to do. In 9.1.3, I had to take a more creative approach. Try the sample below and see if you can make it work for you.
Thanks!
Dan
/* summarize your data */
proc means data=sashelp.class noprint;
class age sex;
var weight height;
output out=class mean=;
run;
/* Adjust some fields for correct plotting */
data class2;
set class;
if (_type_ ne 2) then weight=.;
if (_type_ ne 3) then height=.;
if (sex eq " ") then sex="M";
run;
symbol1 i=needle width=40 color=blue;
symbol2 i=join;
axis1 offset=(5pct, 5pct) minor=none;
axis2 order=(0 to 150 by 25) offset=(0,0);
axis3 order=(0 to 80 by 20) offset=(0,0);
proc gplot data=class2;
plot weight*age / haxis=axis1 vaxis=axis2;
plot2 height*age=sex / vaxis=axis3;
run;