I go to cook college (the science college of Rutgers University) and have learned that deer control how many fawns they have by the amount of food available. this of course was only study. but the study showed that females release more eggs to be fertilized based upon available food. triplets or twins occur when there is alot of food and single or no eggs are fertilized if there is a very high demand on the available food.

i also found it interesting that if a doe has two fawns, they can each have a different father. interesting.