Of course it would be voluntary. Why not offer women under 30 who have been on welfare over two years a financial incentive to take the shot every three months? These ladies are already currently facing financial hardship and are not able to provide for themselves and their current dependents. This financial incentive would benefit the women in their own lives and of course would prevent unwanted pregnancies that either become abortions or more children they can not support. More children for women in this situation will guarantee three things. It will force these women to a longer term of financial dependence on the state, it will increase the taxpayers burden, and the children born into this circumstance have a very low chance of success and prosperity in life. The financial incentive will more then pay for itself, probably 100 fold in reality.