Animals don't have "equal rights". Kovu would be king, simply due to the fact that he would naturally be stronger than the females.
Scar didn't win, because he wanted the power for himself. Seeing as how he killed his brother so that he could be king, you can assume that he wouldn't care about any others being the king.
Argument over.
--------------------------------------------------------------------------- I rock. /--\
--------------------------------------------------------------------------- ~King of Dark~ ♮C.0.W♮ My Past has determined your future My torrential pain will be your unspeakable suffering Your days are numbered Don't fear the end Pray for it and unlike your own immortality My thirst for vengeance WILL NEVER DIE