Deer fawns DON'T have spots, and adult deer DO!
Most people mistakenly refer to young white-tailed deer (and many other deer species) as fawns even when they have long stopped resembling their newborn phase.
A newborn white-tailed deer is usually reddish-brown and covered in white spots which begin to blend into the coat coloration with every passing day after they are born—by winter (around six months), nearly all the spots will have "disappeared." Once spots are almost or completely unnoticeable on white-tailed deer, they are not considered fawns anymore but still not entirely considered adults yet, they are then labeled Juveniles.
Fully grown and mature white-tailed deer still present their spots (which now blend with their surrounding colors much more, but they DO have them for life.