In what way? We change all the time. Parents try to impress cultural norms and qualities. School teachers engage students with qualities of learning. Doctors change the quality of individual's lives through medical interventions and that of groups through inocculations.
(PS please don't shout = use capitals)
Behavioral changes have been made in children as long as parenting existed. Behavioral changes are made in adults as long as jobs and supervisors have existed. I have a daughter who is 29 years old, who has her entire life been on the use of a pacemaker for her heart.
Is this the type of quality you speak?
One of the changes I personally do not like are drug induced changes due to massive amounts of hormones for athletes, such as human growth hormone, steroids, but frankly, these same drugs can have therapeutic benefit for people who are deficit of them. Sometimes the dividing line is not clear...such as in gender changes, or inducing ovulation for women who are older and want to have children. Those are societal issues, in which we take sides, and argue. One of the changes here in my state is the chemical castration of sex offenders in order to get parole, and yes, it is a moral issue, behavioral in nature, and it does make a change in their lives (although the psychological changes do not coincidentally take place). Another issue world wide that has gained prominence because of migration is Female Genital Mutilation (FGM), common in African, Middle East, and the Far East cultures. We recently had a case of it in my area.
So your question is a good one, but it is fraught with moral questions, and to me, the only way to tackle it is issue by issue.