UML14 — OCL specification 1.1, p. 10, 5.4.3, example 3

Summary: Since both expressions start in the same object and one
person can"t have both a wife and a husband, the expression will
never give the result true, only false or undefined

Here one could instead use the syntax of example 1:
self.wife->nonempty implies self.wife.sex = #female and
self.husband->nonempty implies self.husband.sex = #male

Fixed in UML 1.3.