The development of anterior-posterior symmetry of the human embryo occurs during pregnancy. Many of the signals that regulate this process have been described in experiments using mice. However, there is no direct molecular evidence of how anterior-posterior symmetry is achieved in human embryos. Thus, a recent study (see HERE) used human embryonic stem cells – despite the restrictions of embryo experimentation imposed by the Administration.

Human embryonic stem cells continue to be used despite Trump’s restrictions

From a bioethical point of view, these practices have a very negative connotation to generate in vitro three-dimensional models of a human epiblast whose size, cell polarity and gene expression are similar to those of a day 10 human epiblast. According to the authors of the paper, their three-dimensional model may help to better understand the molecular mechanisms that occur to regulate embryonic axial symmetry. From a bioethical point of view, however, it should not be forgotten that human stem cells are being used to produce these epiblastic models and that the embryos from which they are extracted will inevitably be destroyed.