XPath equivalent of a join

<root>
 <class id="1">
   <teacher>5</teacher>
 </class>
 <class id="2">
   <teacher>9</teacher>
 </class>

 <teacher id=5>
   <gender>female</gender>
 </teacher>
 <teacher id=9>
   <gender>male</gender>
 </teacher>
</root>

Is there an XPath statement that selects all of the classes taught by
female teachers (in this case, just the first class)?
The field class.teacher is an id reference to teacher.id.

select class.* from class c, teacher t where c.teacher=t.id and
t.gender='female';