Proper english would regard "male professional" rather than "professional male", as the proper term.
But who can correct the english. (or is it whom could)
It is ''who'' could. ''Who'' is the subject of the sentence, hence in the nominative case, i.e. ''who''. ''Whom'' is used when it it the object of a verb or a preposition, as in, ''according to whom'', or "I don't know whom I hit, but he deserved it.''.
Yours for proper grammar, and FReegards!