HOW CAN A CHILD WITH ONE BLONDE PARENT AND ONE BRUNETTE PARENT BE BORN
WITH RED HAIR?

This previous answer might help:

Genetics
http://answers.google.com/answers/threadview?id=17825

---l

You're not related to me are you? ;) I'm brunette, my husband (and
father of my kids) is blonde and we have a gorgeous red headed son and
a gorgeous blonde daughter. My mother had red hair and Dad had dk
brown hair and they had 6 kids -- no redheads, and out of the 15
grandchildren that these 6 kids produced, there's only been one
redhead -- and I can vouch for the paternity of that one! Her first
great-grandchild, born 2 weeks ago, is also a redhead. I obviously
carry the recessive gene for redheadedness and so does my husband.

Here's a site that might be helpful. http://www.genetics.gsk.com/kids/heredity01.htm

Consider yourself lucky.

I think red hair is gorgeous.

I believe red hair is a mutation.

Its all to do with the allele, if i remember right, hair is controled
by 2 allele (not sure if its a plural word) that are inherited by
father and mother, each child has a random allele from both parents,
as red hair is a resesive allele it must mean that both parants have
one resesive red hair allele in there genes, in this case the
following has happened

R = red  RESESIVE ALLELE
B = Blonde DOMINANT ALLELE
BR = Brunette DOMINANT ALLELE

R-BR  R-B
|    / 
|   /
|  /
| /
RR

in all there is a 1/4 chance of a chile being born with red hair if
both parents have one red allele in there genes

i learned all this doing biliogy long time ago but lots of interesting
article about tis kind of think can be found here
http://www.madsci.org

forinstance, related to red hair, 
www.madsci.org/posts/archives/ may96/828205743.Ge.r.html

and also related to red hair,
http://www.madsci.org/posts/archives/jun2001/993598918.Ge.r.html

mmm think thats all rite, been a while since i done biology

I used to belong to a club for redheads. Once the club took a survey
about redheadedness in the family. The majority of members of the club
reported that neither their father nor their mother was a redhead.
That was the case with my mother. Her parents were both brunets, as
were all three of her siblings. This sort of thing can lead to lots of
jokes about redheaded milkmen.

red hair is an adaptation that occured approx 500,000 years ago to the
inhabits of northern climates, scotland dedmark etc or it is due to
homo sapien cross breeding with homo neanderthalis a resident of these
areas prior to the arrival of homo sapien.

as by one of the other commentors its just a matter of selection at
the moment of conception if the alles for red hairs is present it can
be selected. this is random(almost)

I hate to spoil it for an expert, but if I'm not mistaken, red hair is
a blending of brunette and blonde.  That's why the lineage is so hard
to trace.  Also, I doubt that a parent with blonde hair could have a
recessive red gene.  Darker traits tend to be dominant.  Thus, a
brunette and a blonde will tend to produce brunettes.

We each get one gene from our mother and one from our father.  If both
parents are blonde, all of the children will be blonde.  If one is
brunette, though, there's a posibility that the child will be
brunette.  The reason is that the brunette could be carrying a gene
for lighter hair color, but it's difficult to say.  Even if you can
trace back a few generations and all of the ancestors are brunettes,
there could be that one blonde way, way back that could have passed it
down.

http://www.redandproud.com/The%20Dominant%20Gene.htm

I'm not gonna argue with well-read redheads!

I am BLONDE.  My Mother is dark Brunette, my Father is a Redhead.  I
look exactly like my Father, so there is zero doubt of parentage.  The
Father of my two children is BLONDE as well.

His father died when he was 5, his Mom has had white hair for the 25
years I have known her.  It's too late to call her right now,
otherwise I would ask her.

I was faithful during my marriage.  We had one BLONDE daughter and one
REDHEAD son.  So, two Blondes don't "always" make a Right, ...I mean
BLONDE...

My Son looks a lot like his grandfather, but I named my _Daughter_
after him: Leslie...

~~Cynthia

There are a couple of issues here. One is the complex nature of the
genetics of hair colour i.e. Blond vs. Brunette and the other is the
recessive nature of red hair colour (I'm blessed too!).

There are several genes that contribute to hair colour and even worse
than that there are several versions (us geneticists call them
alleles) of each so you can get many different hair colour and
different combinations of alleles from each parent produce a complex
set of alternatives.

Most Red hair is due to a mutation in the Melanocortin 1 Receptor
which reduces, sometimes to zero, one of the stages in pigment
formation. Only one functional gene is enough so either parent can
have one functioning and one non functioing gene. So there is a 1 in 4
chance that a child will inherit both non functioning copies and will
therefore be unable to fully form pigment. And be blessed with the
finest of hair colours.....

Chris

i am definatly confused by what i have read. My father is a red head
and both his children; me his daughter and my brother are both very
much red heads.
PS red hair is not a mutation its just too cool for ur liking ;) 
i LOVE my red hair it makes us all very special.

I am one of three red-headed children in my immediate family.  My mom
has blonde hair, and my dad is brunette.  Neither of them have parents
or siblings with red hair.  I have on cousin and one great-aunt on my
dad's side who also have red hair.  My late great-grandmother had a
brother with red hair who was appropriately named Rusty.  Other than
that there is no red hair in our family.  If it's true that if both
parents possess a recessive allele for red hair, then they have a 1/4
chance of having a red head, then my parents hit the jackpot!  My
parents were three for three in producing red heads, and I am ever so
thankful for my hair color.  There is no doubt that we were all
fathered by the same dad, so go figure on the chances that they had! 
Feedback from anyone in a similar situation would be great!