They were only forbidden to partake of the Tree of Knowledge of Good and Evil. Some of the best information we have on the Tree of Life comes from I Nephi 11. Nephi is trying to obtain the interpretation of the dream his father had.
Factors that increase the risk of prostate cancer include: older age, a family history of the disease, and race. About 99% of cases occur in those over the age of 50. Having a first-degree relative with the disease increases the risk two to threefold.
All types of prostate cancer treatment can cause erectile dysfunction. In the course of removing the cancerous prostate gland, due to their proximity, the nerves responsible for erection are often damaged. Additionally, radiation therapy of the prostate can lead to blockage of blood flow into the penis by damaging the penile arteries. Hormonal therapy will cause lack of desire and arousal as well as the inability to obtain a full erection.