Should the United States limit scientific advances?

Primary Sources (first-hand research): I plan on interviewing my past physics teacher,who has a PhD in science and has worked in many major scientific advances in Russia. I will ask him questions such as:
-what could the downside be of cloning, stem cell, and A.I.?
-how close do you believe we are to achieving any of the above to their fullest?
-what are potential positives of stem cell, cloning, and A.I.?
-do you think there should be a limit set on how far science can advance?
-what limits are already set?
Secondary Sources: I will examine the laws already in place in the U.S. that limit scientfic advances, examine what progress has already been made in cloning, stem cell, A.I., examine the counter arguements and what groups oppose or support scientific advances.