what is the opinion of buddhists about genetic manipulation and eugenetica?

Answer 1

I study buddhism and this is my opinion: since most humans have not attained wisdom in the sense of knowing ALL the possible effects of their actions, manipulating genes is quite dangerous and could result in a great damage to future generations.
One thing is modifying corn kernels to make stronger and more abundant crops to feed the hungry, altering human genes to get strong, good looking people is very different.
Only illuminated beings (Buddhas) can see all the future repercutions of any action, and I am not sure genetic scientists, no matter how brilliant they are, are Buddhas.
If by eugenetica you mean the "disposal" of beigns that do not conform to "high quality" genetic standars, that would be considered a murder, as I see it. So, as with any negative action, negative consequences will follow.
As far as I know Buddhist schools do not explicitly oppose to these practices (Buddhism does not condemn, only shows the logical consequences), but the buddhist scholars and teachers warn their students about the possible results of such efforts.

Answer 2

Explicitly, no opinions or explanations! By inference, manipulation of the mind through rationalisation of desires and expectations to get rid of 'misery' ("Desire is the cause of misery"!) and frustrations in order to find peace and balance of mind, is recommended!

Answer 3

If it will lead to suffering for oneself or others, it should not be done. If it will lead to the cessation of suffering for oneself or others, it may be done.