Dr David King, director of Human Genetics Alert, told ITV News the "three parent" IVF technique crosses a "crucial ethical line":
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Pro-Leave campaigner Boris Johnson has responded in a politely worded letter to Jean-Claude Juncker's invitation to "come back to Brussels".
The Friends star had reportedly not seen her mother for several years following a feud - but reconnected with her shortly before she died.
A deal is believed to have been reached with official confirmation likely on Friday.