Cloning Cloning is a hot topic several years ago . Since the cloned sheep , Dolly , was cloned , some scientists are trying to clone human beings. And some men have a fantasy to clone themselves. In my opinion , cloning human beings is unethical. If a man is cloned , he is not the miracle of life . He is a product , just like people manufacture produces. What's more , once a cloned man is born , how would he feel when he grows up?When he realizes that he is not a man reproduced by his parents , he will feel he is different from others . This would leave a pain in his fragile heart. The birth of human beings is a fantastic and tough process, not just an experiment in the laboratory . Firstly, the fusion of sperm and egg is beset with difficulties. Thousands of sperms head for one egg . Only one can combine with the egg successfully. When the egg is fertilized, it takes several day to develop into embryo. Finally , the embryo become a baby . The birth of baby brings happiness to the family . Cloning mammals is not a wise option if it is not necessary . Cloning takes a long time to experiment on mammals. It is a waste of time and material . Of course , we can't consider cloning as a useless technology . For instance, we can clone mammals that is going to be extinct. Or we can clone a man's organ which can transplant into the man's body when the man picks up a disease. In a word , cloning should be developed carefully .