You have to consider the biology of your area. It's pretty complex, and you can't make any kind of 'general' statement that covers the whole country.
Consider this:
Any juvinile animal will consume a huge amount of the available food, and cannot reproduce. Many will not survive until the age where they can produce young. IF the population of younger animals is very high - this can dramatically affect the amount of food available for older animals.
A reduction in forage can also lead to weakness and death amongst the juviniles - if you have too many kids, a higher percent of the kids might die off - a few less kids and more may actually survive.
Killing a doe has the largest impact on how many fawns there will be the next year as maddog mentioned.
Now - keeping that stuff in mind, you can see where the ministry will examine the situation in each area.
If there are too many fawns being born - they may well decide to tell hunters to start taking out the does. This can lead to a higher SURVIVAL rate amonst the other fawns.
If there are just a FEW too many fawns, they may encourage people to take spikes. A few less juviniles and things get better, without massivley reducing the juvinile population.
If things are stable, they may restrict it to adult bucks. You can remove a fair number of adult bucks without necessarily affecting the birth rate the next year.
I'm giving the 'quick and dirty' simplistic view of things - but you can see it's a very complicated issue. Less deer born can actually mean MORE deer in the area in many cases - Or it can mean healthier, stronger and bigger deer (better food supply) who are more able to resist a bad winter.
It's up to the biologists and hunters in an area to figure out whats right for that area.