This type of procedure involves implanting dopamine producing cells in the striatum to compensate for loss of dopaminergic nigrostriatal neurons. Fetal tissue is obtained from elective abortions in which the fetus is between 6 and 8 weeks. Fetal dopaminergic neurons are used because they can survive for long periods in host striatum, they are capable of forming synapses with striatal neurons, and they actually produce dopamine. The tissue is implanted stereotactically in the striatum. It takes varying amounts of time to be effective, between 1 and 3 months. (Krauss, 1996) Even though this is a new and experimental procedure, it is raising lots of controversy. Obviously there are ethical issues surrounding the use of fetal tissue, and scientists are not sure what patients will benefit the most from this. From the entire discussion of surgical procedures, it is clear that none of the surgical procedures are perfected yet. It is probable that the ones most commonly used in the future will be those that produce the longest lasting effects with the fewest side effects.