there are two ways of looking at this. one is that nature has provided almost all sprouts with a certain amount of toxins, this ensures that animals do not eat all the young shoots and gives the plants a chance to mature and carry on the life cycle. the other is that immature plants are just not good for you and that you should wait until they are mature, as that is when the nutrients become bioavailable.
with sprouts it is a give and take thing. sure there are some toxins, but they are also packed with wonderful nutrients so is the pay off worth it? i say it is, and i eat them everyday.
as far as the gerson diet goes, that diet is very very specific as to what it allows in and doesn't allow in. it is not saying sprouts are bad period, it is just saying that when you have cancer they are not very good, like a lot of other foods. that diet eliminates ALL possible carcinogens in an attempt to allow the body to heal itself.