What are the odds of two left-handed people having all right-handed children?

Question

My parents are both left-handed. My two sisters and myself are right handed (I am in the middle). What are the odds of this?
What are the odds that the first child would be right-handed (based on 2 left-handed parents)?
What are the odds that the second child would be right-handed (based on 2 left-handed parents)?
What are the odds that the third child would be right-handed (based on 2 left-handed parents)?
Please answer using the laws of genetics, and stating any sources/credentials, if possible.

Answer 1

Firstly I am no scientist but I've taken Bio 30 and know some basic Mendelian genetic laws. While genetics in human beings are more complicated than in Mendel's pea plants the basic laws would still apply.
Assuming that left-handed ness is a dominant allele we must assume that both of your parents are heterozygote. Each has a 1/2 chance of giving the recessive right handed allele.
when mulitiplied it shows that there would be a 3/4 chance that the first child is left handed and a 1/4 chance they would be right handed (like you and your sisters)
the same probabalitly would apply to the second and third children. (though to have two children in a row it would become 1/16 and three in a row is 1/64)

that however is all assuming that 1. left handed is dominant and 2. that human genetics are that simple(which they are not)
so basically none of this can really be backed up.

but if this question is purely for anecdotal uses your set- just through in a few big words and your audience will be impressed.

look it up on wikipedia... that should be more reliable.

Answer 2

Can't give you the odds (sorry) but right-handedness is dominant, so it is certainly possible genetically.

In my family of origin, my father was left-handed and my mother is right-handed. My brother and I are both left-handed and we both look like Dad, so I never had cause to doubt my mother in that regard.

Answer 3

My wife and I are both right handed, however our three children are all left handed. (no twins or triplets)

Answer 4

thanks for the points!