Designing a baby means that through selecting a proper embryo by PGD (pre-implantation genetic diagnosis) technology, and implanting it into a women's womb, a baby is born at last.It brings blessing and potential threaten at the same time.This problem arouses disputes in moral and ethical levels, and challenges legislation too.It is meaningful to discuss what legislative standpoint should be held toward designing babies.Permitting under certain conditions might be a reasonable solution.