Three parent babies - but only males

Xavier Symons
February 6, 2016
Reproduced with Permission

The US National Academies of Sciences, Engineering and Medicine has recommended that US government allow mitochondrial DNA transfer in male embryos. The Academy made the recommendation in report issued last week, entitled Mitochondrial Replacement Techniques: Ethical, Social, and Policy Considerations.

The report's authors recognize the ethical complexities of the procedure, which was approved by the UK Parliament last year, but nevertheless suggest that the DNA alterations involved are minimal enough to make it ethically permissible. As stated in the abstract:

"...While significant ethical, social, and policy considerations are associated with MRT, the most germane of these issues can be avoided through limitations on the use of MRT or are blunted by meaningful differences between the heritable genetic modification introduced by MRT and heritable genetic modification of nDNA. Therefore, the committee concluded that it is ethically permissible to conduct clinical investigations of MRT."

Oddly enough, the report argues that the procedure should be limited to male embryos. The authors state that it is prudent to minimise the dangers of 'passing on' adverse effects of the procedure to future generations, and one way to do this is to begin with males only:

"Intrauterine transfer for gestation [should be] limited to male embryos in order to prevent potential adverse and uncertain consequences of MRT from being passed on to future generations".

Later in the report they proceed to outline the conditions for an ethical expansion of MRT research to include transfer of female embryos.

The sons-only recommendation has been criticised by researchers in the UK, whose parliament gave the go-ahead for mitochondrial replacement therapy last year without any such restriction.

"I think the UK came to the right conclusion," says Alison Murdoch of Newcastle University in the UK, whose team is developing mitochondrial replacement therapies. "This would rather defeat the purpose of what we are trying to do."

At the moment, these recommendations are no more than discussion points, as the FDA is unable to authorize the procedure without Congressional approval - which seems unlikely in an election year.