Can two brown eyed people with brown eyed parents have a blue eyed baby?

Question

I already understand the brown dominant, blue recessive gene concept, and that brown eyed people who carry a blue recessive gene can have a child with blue eyes, but what I need to know is how many generations can a blue eyed recessive gene stay in a family?
Example- Baby has blue eyes (for 1year, assuming they'll stay blue) Mom and Dad both have brown eyes. Dad's parents both have brown eyes, as do 3 of 4 grandparents (babies great grandma has blue eyes) Mom's parents both have brown eyes, but mom's grandparents are unknown.

SO Can a blue eyed gene from your paternal grandmother, and only your paternal grandmother, cause you to have blue eyes? Or are the babies' blues because Mom's ex boyfriend has beautiful sky blue eyes?
Or in ex.2, if baby has blue eyes, mom and dad have brown eyes, and dad's parents had brown eyes, but one of mom's parents had blue eyes, could one grandparent with blue eyes cause you to have blue eyes?
What's the least it would take to have a blue eyed baby?

I already understand the brown dominant, blue recessive gene concept, and that brown eyed people who carry a blue recessive gene can have a child with blue eyes, but what I need to know is how many generations can a blue eyed recessive gene stay in a family?
Example- Baby has blue eyes (for 1year, assuming they'll stay blue) Mom and Dad both have brown eyes. Dad's parents both have brown eyes, as do 3 of 4 grandparents (babies great grandma has blue eyes) Mom's parents both have brown eyes, but mom's grandparents are unknown.
SO Can a blue eyed gene from your paternal grandmother, and only your paternal grandmother, cause you to have blue eyes? Or are the babies' blues because Mom's ex boyfriend has beautiful sky blue eyes?
Or in ex.2, if baby has blue eyes, mom and dad have brown eyes, and dad's parents had brown eyes, but one of mom's parents had blue eyes, could one grandparent with blue eyes cause you to have blue eyes?
Please explain answers, links if possible!

And blue eyes are recessive, not dominant.

according to highschool and college bio, baby with blue eyes would have to be bb. Dad is BB, because one parent is BB and the other is bB, and mom is BB because as far as I know both parents are BB.

BUT if dad is BB and mom is Bb, then the 4 outcomes would be BB, BB, Bb and Bb, and the only way to actually HAVE blue eyes is to have bb, so according to this, baby can't have blue eyes, baby can only carry the b gene...no?

wait, wow. On the paternal side, If one of 4 great grandmas was bb, then grandma could have been Bb OR BB, even though she has brown eyes, and even though grandma and grandpa both have brown eyes, Grandma could still have passed down the Bb gene to Dad, even though dad has blue eyes, correct? so basically dad COULD be Bb, and mom we think could be Bb, though both parents have brown eyes as well. so baby could theoretically be bb. is this correct? or am I mistaken?

Answer 1

Well let's see...

(B denotes brown, b denotes blue)

father's side
grandfather: BB
grandmother: Bb (since you said she has brown eyes too)

Father:
BB/Bb (assuming Bb for sake of the exercise)

mother's side
grandfather: BB
grandmother: BB
Mother: BB

mother X father = BB X Bb

Baby is either BB or Bb... it is genetically impossible for him to have blue eyes. However, it doesn't mean the blue eyed gene can't be passed down, as it very well might be, should the baby have Bb.

Hope I helped.

Answer 2

The least it would take is both parents having Bb (dominant/recessive) genes. That can be carried on for many generations. Although with two brown eyed parents, the best odds (assuming both parents carry the recessive gene) are 1/4 that the baby will have blue eyes. 1/4 will carry BB genes and 1/2 will carry the Bb genes.
So, half the people out there with brown eyes have the POSSIBILITY of having blue eyed babies.

Answer 3

First, the blue eyed concept COULD happen, depending on how many generations back it happens--ie: great grandma 1x? Good possibility--great grandma 3-4x back or further makes the chances dimmer. The answer to your paternal question: Because the grandmother had blue eyes, there's a strong probability that blue eyes ran in the family on one or both sides of her family. It COULD BE a recessive trait, as is the case with one aunt in one side of our family but the first speculation is the one "I'd throw money on the table" to win on. With so many blue-eyed people vs. brown eyed people in the equation, the baby's eye color is 50-50, although don't rule out green. Sometimes, if there is enough brown and blue in the mix the result CAN BE green. The blue has to "run deeply" for blue eyes. The least it would take to have a blue eyed baby: Boyfriend, mother, grandmother all have blue eyes--I'd be shocked if "little darlin'" didn't have them too with all that blue---110% certainty of it with all of that.

Answer 4

My daughter and her boyfriend both have dark brown eyes. Their son who is 17 months old still has bright blue eyes much to my surprise. I know they can still turn but his mom's eyes were brown by the time she was 3 months old. As far as the family on both sides. His side all have brown eyes. My husbands side has either brown or hazel. My side, brown, hazel or green. Nobody exept the baby has blue eyes. My youngest two children both had blue eyes until they were about 5 or 6 then they turned green. So just because the baby's eyes are blue now doesn't mean they will be later.

Answer 5

Blue eyes are due to a recessive gene, if one parent has brown eyes, then their babies are more likely to have bown eyes. But, you inherit one eye colour from your mother and one from your father, who also inherited one colour from your grandmother and one from your grandfather, the list goes on, so to answr your question, yes, two ble eyed parents can have a brown eyed child. I know two brown eyed parents who have a blue eyed child, and a gray eyed mother and brow eyed father with a green eyed child, so nothing's impossible! If you have that litle bit of brown around the pupils, then it's just a small variation in the gene passed on, and not due to a brown eyed gene inherited from your parents. Chances are, a parent, grandparent, even great grandparent might have had the same variation and it's lain recessive until it cropped up in you!

Answer 6

genes are crazy little things. Seeing that you already know that there is a blue eyed gene in the blood stream, then why are you asking this question? Yeah, there is no question that the kid just got the gene. Good for him/her. I have a friend who is african american, and both her parents are african american as well as her husband and his parents, grandparents etc., but i think that her great-great grandparents, one was white, well last year, she had a beautiful baby boy, he's light-skinned with grey eyes and curly hair. Like i said, genes are crazy things that cannot be controlled!

Answer 7

The old teaching of brown dominant, blue recessive, has proven to be false. It's more complicated than that. Eye color has since been discovered to be a polygenic trait, that is, not one gene is responsible for eye color.

It's possible for brown eyed parents to have a blue eyed child, or for blue eyed parents to have a brown eyed child.

Scientists from Australia have made a recent breakthrough discovery in the genetics of eye color. Here an article from the BBC about it http://news.bbc.co.uk/2/hi/science/nature/6195091.stm

Answer 8

yes brown eyed people can have a blue eyed baby. You wouldn't know where the blue eye genes came from without dna testing. but bothe the mom and dad gave a blue eye allelle to the baby. a blue allele could have traveled for generations in heterozygotes. then 2 heterozygotes mated and made a homozygote.

Answer 9

all my sis ters and all my cousins including my self which numbers 8 in all between us we have 14 kids all but one have dark brown hair ,dark brown eyes, and a dark olive complexion my husband is half native american the rest eastern european like my self he also has be,bh, our daughter has bright red hair (like bozo), the bluest blue eyes, and fairer than snow white skin and yes in the delivery room there was the speculation as to wither this was his or "the milkman's baby" so it does happen the thing about my sisters and my cousins is that our parents are both sets of twins that married each other so our genetic make up is the same because our parents and my aunt and uncle were both identicals so 1 out of 14 isn't bad we have traced back about 200 years but still have not found any irish so she's a mystery

Answer 10

First of all, understand that blue is a dominant gene, according to the last A&P class I took in college. It's pretty easy to have a blue eyed baby no matter what color runs in your family.