A number of genetic disorders result in irreversible damage to the fetus before birth,as well as for those with genetic disorders who may benefit from therapy before symptoms are manifested.

• 许多遗传性疾病导致胎儿在出生前就受到不可逆的损害，还有一些遗传性疾病在症状表现明显以前如果获得治疗则可以从治疗中获益。