The experiment helps fulfill one of the promises of embryonic stem cell research, Eggan said.

这项实验有助于完成胚胎干细胞研究承诺中的一项，Eggan说。

These viruses integrate into the cells, making them far too dangerous to use in people, Eggan said.

这些病毒整合进细胞，使它们应用于人类简直太危险了，Eggan说。

Eggan said this does not mean it is no longer necessary to use the controversial methods to get real embryonic stem cells by using human embryos from fertility clinics or by using cloning technology.

Eggan说这并不意味着不再有必要利用有争议的方法，通过从生育门诊来人类胚胎或利用克隆技术，获得真正的人类干细胞。