Blood type question

**Firedemon** · 2014-08-19 19:10

So my wife's biological father passed away last week, and we're in the process of family history (he was adopted), and we're trying to narrow down what his blood type was (doctor is being a dick about confidentiality).

My wife and her brother are both B- with their mom AB+. Their half-brother (same dad) is also B-. Is there any way to determine what his blood type was, or will that just narrow it down without a definite answer? It just seems too much of a coincidence that 3 children all have the second most rarest blood type.

Thanks if anyone knows this.

**Necronus** · 2014-08-19 19:19

http://www.endmemo.com/medical/bloodtype.php

**Firedemon** · 2014-08-19 19:23

The problem with that calculator is that it narrows it down to A/B/AB/O+, which doesn't really help much.

**synistar** · 2014-08-19 19:31

Given the combination, it's not possible to narrow anything down. Father could have been any genetic combination (O/O, B/B, A/B, A/O, B/O) except for A/A. Probability can't give you a definite answer because genetics is completely random.