what is the probability of two brown eyed parents having a green eyed child?
It depends on how often their mobile homes caught fire.
But seriously, folks… Based on the info you gave it’s really not possible to give you a probability.
First of all, eye color is a polygenic trait as far as I know. In other words there’s no single eye color gene. So that prevents us from doing the basic genetic probability check.
Secondly, you only described the phenotype (appearance) of the parents and not the genotype. The genotype would indicate if either parent carried the genetic material allowing for the possibility that offspring could have green eyes.
There really is no way to accurately compute this probability based on your information.
My guess is that if both parents have one green eye gene and one brown eye gene, then the odds are 1 in 4 that the child will have green eyes (because the child will have green eyes only if they get a green gene from both parents).
But there’s no way to calcuate the “odds” that both parents have one of each gene, I don’t think. I would think that the majority of brown-eyed people have one brown and one blue gene, simply because blue eyes are so common. So we can probably conclude that the odds are kind of low that two people with the unusual combination of green/brown would marry each other.
All just guesswork, of course. 
You are probably adopted.
Before you ask for your adoption papers, search this forum for previous eye color threads. There are at least two.
Try: eye color, blue eyes, green eyes, brown eyes, eye and hair color and one of those will get you to the right place.
jois
Heheheheh!! You said “green gene!”
Ahem. Anyway…the simple dominant/recessive trick only works for brown and blue, as I recall, green, hazel, and gray involve other genes and is more complicated.
It is definately more complicated! We are not dealing with pea plants here people.
Genetics guys have this two gene theory about eye color. One gene is green/blue the other brown/blue. Green is dominant over blue. Brown is dominant over blue. Brown is also dominant over green. This theory does not account for weird ass eye colors like gray and what not, but it’s a good start.
Lets say:
Mom is G-G on the green/blue gene and B-Bl on the brown/blue gene.
Dad is G-G on the green/blue gene and B-Bl on the brown/blue gene.
Both parents display brown eyes, and there is a 1 in 4 chance that junior is green eyed.
That’s the first explanation of eye color that I’ve seen, Lance. Cool.
Reminds me of Labrador retrievers, whose coat color depends on two genes. One determines pigment type (black is dominant, “chocolate” is recessive), the other determines whether or not that pigment will be deposited in the hairs (deposited is dominant over not deposited). Lack of pigment deposition produces golden labs. So color depends on both sets of genes.
Once you start talking calico cats and agouti mice, it gets even more complicated. The genetics of pigmentation in general is very complex. Recessive epistasis, modifer genes, suppressor genes, complementation, codominance and multiple alleles are all involved in pigmentation. It’s not just a case of one gene either being “on” or “off”.
In other words, you get a damned ugly Punnett square.
Of course we are. Here is the site where you can breed your own peas online. These are green-eyed peas, but there are black-eyed peas as well.
http://www.sonic.net/~nbs/projects/anthro201/exper/
Peas, brother
-G. Mendel
Or colors of normal ass eyes, either.
That’s all I really had to say. I’m not up on my eye color genetics.
Bear_Nenno was correct. We are not discussing pea plants.
tcburnett, tinker with The Eye Color Calculator; it is more appropriate to this thread.
Are hazel eyes really that complicated? That’s interesting. Don’t many people who have blue/green hazel eyes have flecks of yellow in there that make them appear green when the light hits them right? I didn’t think it was all that genetically complicated. My daughter has strange colored eyes, so does my younger sister. Both of their fathers had dark green eyes and my mother and I have typical red/brown. Both my sister and my daughter ended up with this odd color that is much lighter, often photographs blue, looks green, turquoise or gray when you look straight at them. My neighbor who was Portugese called them tashelmara (unsure of spelling). Very interesting posts.
Needs2know
Bless your heart, Wood Thrush, several of us have just worn our fingers to the bone 1. explaining that eyes aren’t single simple pea picking flower simple and 2. looking for a site with a reasonable explaination on the net. Thanks!