Tissue containing totipotent embryonic stem cells is difficult to obtain; what is the usual source?

Question

Quizplus · Accepted Answer

The usual source of tissue containing totipotent embryonic stem cells is the donation of surplus blastocysts produced by in vitro fertilization for women seeking fertility treatment. This is because the blastocysts used in IVF treatment are typically not implanted in the patient and can be donated for medical research instead. The other options (A, C, and D) involve the use of tissue from miscarriages, elective abortions, or the placenta after birth, which may not always contain totipotent stem cells or may raise ethical concerns.

Tissue Containing Totipotent Embryonic Stem Cells Is Difficult to Obtain;