Genetic therapy and engineering
a.
have no value for our future
b.
have been used for many years to prevent genetic diseases
c.
are simple procedures that most doctors can perform
d.
are controversial scientific procedures

D. are controversial scientific procedures

Explanation:

As the name suggests, both therapy and genetic engineering refer to genetics, that is, genes and DNA molecules, responsible for our biological inheritance. There are thousands of genes in our cells and each has a code capable of activating a specific function of the body. What researchers working with engineering and gene therapy have tried to do is to reprogram this genetic information so that the cell's instruction is, for example, to attack cancer.

These two strands are extremely controversial, because they deal with a very delicate and powerful molecule, DNA. Many find it dangerous to interfere with the way our DNA works, while others believe that for religious reasons it is not correct to tamper with the human body at the cellular and molecular level.