Is it true that 2 RH positive parents cannot have 4 RH negative children? Is 3

Question:

Is it true that 2 RH positive parents cannot have 4 RH negative children? Is 3 the maximum?

Best Answer - Chosen by Asker: It depends on what your genotypes are.

If you are both + +, then ALL of your children will be + +.

If you are both + -, then your children have a 1/2 chance of being + -, a 1/4 chance of being + +, and a 1/4 chance of being - -.

If one of you is + + and the other + -, then your children have a 3/4 chance of being + + and a 1/4 chance of being + -.

There is no "maximum." You could be a + -/+ - couple and have twenty children that are - - although that is quite unlikely.

By the way, positive genotypes are considered + + and + -. The negative genotype is - -. The + gene is dominant.