Assertion: chimera's cell | /r/MadeOf | a y chromosome
Facets:
Source sentences:
text: The researchers knew that the cells were from the fetus, and not from the mother, because the cells contained a Y chromosome (found only in males) and the women had all been carrying sons.
text: Identifying these different cell lines can be complicated, so researchers focused on women who were all mothers of sons so that any cells containing a Y chromosome could be easily associated with the baby’s cell line and not their own.