If aliens from another planet came to earth, they would almost certainly view men and women as two different species.
Actually, many men and women view the other sex as a different species...:)
Time or Newsweek, believe it or not, back in the late 80s:
“If aliens from came to earth and saw the vast array of career and life choices available to women, and the automated, electronic devices that ease and simplify modern women’s traditional or chosen roles, the aliens would likely comment that no one group has ever had so much freedom and self-determination. And they would likely be vehemently condemned and villified for saying such.”