• A POSTnote on regulating germline therapies will look at new genome editing techniques and how they could be used to edit human eggs, sperm, or embryos.
  • It will examine current definitions, applications, alternatives, and concerns surrounding germline therapies.
  • Work on this POSTnote has been completed. You can read the published report online. Updated 21 January 2020.

New genome editing techniques for modifying DNA could potentially be used to modify the DNA present in human eggs, sperm or embryos. Any such changes would be passed on to future generations (so-called germ-line therapy). While such approaches have the potential to correct the mutations that cause serious genetic disorders, any unintended modifications would also be inherited.

To date there has been a consensus that it would be “inappropriate to perform germline gene editing that culminates in human pregnancy” because of safety and ethical concerns. However, in November 2018, a researcher at a University in Shenzhen, China, reported using genome editing to modify the DNA of twin girls to make them resistant to infection by HIV.

The study has yet to be published in a peer-reviewed journal, but the announcement provoked outrage among the wider scientific community. It also triggered on-going debate about what exactly constitutes a germline therapy.

For example, some scientists suggest that treatments could be regarded as germline therapy because they interfere with the flow of genetic information from one generation to another. There is also a lack of clarity over whether treatments that change the chemicals attached to a DNA sequence (so-called epigenetic changes) would constitute a germline therapy.

A POSTnote on this subject could outline the various possible definitions of a germline therapy, the potential applications of the techniques involved, and the possible alternatives. It could also examine the safety, ethical, legal and regulatory issues the use of such techniques raises.