Altering the DNA of humans - should we allow gene editing?
Should scientists be allowed to do research which alters the DNA of human embryos?
It is a question being discussed by hundreds of scientists from 20 countries in Washington, at a conference on what is known as gene editing.
The technology makes it possible to change the genes parents pass on to their children.
It might help prevent inherited diseases - but it also gives rise to fears about creating designer human beings.
Fergus Walsh reports.