Sexual offences and forensic psychiatry: superfecundation: practice question

A Forensic Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

Try it

Forensic Medicine · Sexual offences and forensic psychiatry: superfecundation

Sample item

A woman has intercourse with two different men within a few days of ovulation and later delivers twins. DNA testing shows that the twins have different fathers. Which term describes this?

AChimerismBSuperfecundationCSuperfetationDPolyspermy

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Superfecundation

Superfecundation is the fertilisation of two ova released in the same cycle by sperm from separate acts of intercourse, so twins can have different fathers. Superfetation is the fertilisation of an ovum from a later cycle during an existing pregnancy, giving fetuses of different gestational ages. Both are rare.

Option by option

A. Chimerism
Chimerism is the presence of two cell lines in a single individual.
B. Superfecundation (correct)
Correct. Two ova of one cycle are fertilised by sperm from different acts.
C. Superfetation
Superfetation involves an ovum from a later cycle in a woman who is already pregnant.
D. Polyspermy
Polyspermy is entry of more than one sperm into one ovum.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is B, Superfecundation. Superfecundation is the fertilisation of two ova released in the same cycle by sperm from separate acts of intercourse, so twins can have different fathers.

Why is "Chimerism" not the answer?

Chimerism is the presence of two cell lines in a single individual.

Why is "Superfetation" not the answer?

Superfetation involves an ovum from a later cycle in a woman who is already pregnant.

Why is "Polyspermy" not the answer?

Polyspermy is entry of more than one sperm into one ovum.

What concept does this question test?

It tests Sexual offences and forensic psychiatry: superfecundation in Forensic Medicine. Superfetation is the fertilisation of an ovum from a later cycle during an existing pregnancy, giving fetuses of different gestational ages. Both are rare.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Sexual offences and forensic psychiatry: superfecundation?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.