Which statement is true regarding conjoined twins?
A) Splitting of the inner cell mass may have occurred before gastrulation.
B) Surgical separation is nearly impossible even with minor fusion.
C) Separation of the blastomeres early in cleavage may have occurred.
D) Splitting of the blastomeres or of the embryonic disc is not complete.
E) Two separate oocytes are fertilized at the same time.

Question

Quizplus · Accepted Answer

Conjoined twins occur when splitting of the blastomeres or of the embryonic disc is not complete. This occurs during cleavage, when the developing embryo divides into multiple cells. If the division is incomplete, the resulting embryos may remain attached and develop into conjoined twins. Surgical separation can be difficult depending on the extent of fusion, but it is not impossible. Splitting of the inner cell mass or fertilization of two separate oocytes would result in completely separate embryos, not conjoined twins.

Which Statement Is True Regarding Conjoined Twins