This is my favorite aphorism

Everyone chooses for themselves
Women, religion, the way
to serve the devil or
the prophet
Everyone chooses for itselves.

My translate from Russian.

Everyone chooses for themselves...or to be really accurate..himself (herself is understood since Everyone is singular). However, to be politically correct, one can also say everyone chooses for himself/herself.  Itself does not apply to people.  Themselves can be used when you talk about more than one person:  they fed themselves at the dinner. Of course, in informal English, themselves has come to mean himself/herself.