Ever since the ability to filter desirable and undesirable traits from our offspring became a possibility, there has been heated debate over the implications of playing "god". Already, it is possible to have one's DNA tested and evaluated for increased risks to certain hereditary diseases. With advances in in vitro fertilization, it may also be possible selectively implant embryos with specific traits (a la the movie Gattaca).
In society's current state, such biological experimentation is often frowned upon. It is seen as unnatural and potentially unjust - only the wealthy would have access to procedures and hence, they would only become wealthier. In addition, much of the motivation for such technology is selfish. Increased intelligence or longevity only potentially benefits an individual...
...but what if such technology could eliminate a societal problem like hate? (Assuming that nothing else - like anger or love - is eliminated concurrently)
First imagine a world without hate. What would it be like? Would 9/11 have happened? Would there still be conflicts and warring in the middle east? Would riots and hate groups still exist?
Next, consider: If genetic modification would make the world a better place, shouldn't science pursue that option?