Embryonic blemishes

July 17, 1998

It is unfortunate that the picture chosen to illustrate the article "Engineered to perfection" (THES, July 10) about the issues surrounding pre-implantation genetic diagnosis was misleading, as were certain aspects of the text.

The embryo in the pictures has been developing for four weeks, whereas embryos used for pre-implantation genetic diagnosis are only three days post fertilisation. They consist of just eight cells, a tiny ball almost invisible to the naked eye. At this stage, it has not even been determined which cells will form the embryo and which the placenta. This is why it is sometimes called a pre-embryo.

Because the genetic testing is performed at such an early stage, embryos have to be generated by in vitro fertilisation. They are not removed from the mother; this would be impossible to achieve at a sufficiently early stage.

Joy Delhanty Human genetics group University College London

Please login or register to read this article.

Register to continue

Get a month's unlimited access to THE content online. Just register and complete your career summary.

Registration is free and only takes a moment. Once registered you can read a total of 3 articles each month, plus:

  • Sign up for the editor's highlights
  • Receive World University Rankings news first
  • Get job alerts, shortlist jobs and save job searches
  • Participate in reader discussions and post comments

Have your say

Log in or register to post comments

Most Viewed


26 September

Most Commented

Universities in most nations are now obliged to prioritise graduate career prospects, but how it should be approached depends on your view of the meaning of education. Academics need to think that through much more clearly, says Tom Cutterham



Head of Ventures

Kings College London

Director of Drama St Mary's

St Marys University, Twickenham

Head of Operations

University Of Leeds

Senior Project Manager

Queen Mary University Of London