A team of American and British biologists has successfully kept a human embryo alive in the lab for 13 days, breaking the previous record of nine days. This achievement has revealed some unknown details of the first stage of human development and has been a major step in understanding why so many failures occur during in vitro fertilization.
The same experiment also touches upon ethical dilemmas. About a dozen countries agreed to set 14 days as a limit for lab experiments involving a human embryo, implying that an embryo older than 14 days should be considered a human with rights. It is recognized that 14 days is when the fertilized egg starts to show a human form. It is also the time when the cells start to split and develop separately in case of twins. Researchers have been trying to push this limit further, stressing the potential benefits of this study: “We discovered, in the human embryo, a population of cells that nobody else has ever seen in any other animal. Not knowing that this is part of our anatomy – at the beginning of the 21st century – is a little bit, how shall I say, embarrassing” says Ali Brivanlou, professor at Rockefeller University and an expert in the field.