Is the ‘black’ skin colour gene always dominant? I’m just thinking to cases within my neighbourhood and circle of friends, kids that are born to one black parent and one white parent are always black, without exception from my experiences.
It’s perception, isn’t it? To a (fully) black person, the child of such a relationship may well look white.
Actually, this is quite interesting, and something I’ve wondered about myself, except, in my experience, the converse has been true, although, I’m thinking about a scenario where one parent is white, and the other is of Indian sub-continental extraction. The kids always appear extremely pale-skinned, but always have dark hair. I know that the dark hair gene is dominant, so that doesn’t surprise me at all, but the consistently pale-skinned characteristics do.
How are you defining “black”? I’ve known a few folks of mixed parentage, and haven’t noticed a trend that the kids tend toward the skin tone of their darker parent.
I have a friend who is half black and I had no idea until somebody told me.
A long time ago, I had a job where coding answers was part of what I did. One of the questions I would code was race. Some people would answer ‘half black, half white’. They would be coded as black for no other reason then the studies would have less blacks than they should (more serious studies would have asked questions to gauge ethnicity-- how the respondent views themself.
Anyways…
We had an employee who was of Japanese origin. She had very strong ties. She questioned our process of above. When I told her why it was done this way she still seemed to think it wasn’t correct (and she would be right 
)
One day I asked her out of the blue “Hey xxx, I have a guy here who says he is half Black and have Japanese. Should I code him as Black or Asain?”
Without hesitation she said Black. She took quite a bit of crap from coworkers.
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The way it seems to work is that there is the dominant ‘race’ of the area. It is ‘pure’. Any ‘contamination’ of this race throws the person into the non-dominant class.
Here, half Japanese/half Caucasian would be Asian. In Japan, it would be Caucasian.
Please disregard the 50 million spelling errors above. 
This is a loaded question, in that it brings up all sorts of things about race relations in the US. If you read, for instance, Loewen’s books on US history and the way it’s taught, you’ll learn how , in the old South, having any black people in your background made you “black”, and effectively disenfranchised you – you couldn’t vote, etc. So this is a touchy question.
From a scientific point, I’m not sure the question has meaning – we’re all mixes of traits that go all the way back to when homo sapiebns was defined. What is “black”? . The distinctions of mulatto, quatroon, octaroon, mestizo, etc., are, I believe, all the legacy of a racist past.
In college, I knew a guy who had one black parent and one white parent. He was quite pale in skin tone and “looked white” to me (I’m white), and then I met his brother (same parents) who “looked black” - he didn’t have the deep, deep skin tone that you sometimes see, but he was darker in complexion than, say, Halle Berry.
Since then, I’ve met a guy who “looks white” to me (looks like he has a fairly light tan, perhaps) but has one black parent and one white. His sister, also of the same parents, “looks black.” He’s said that his perceived race depends on who’s judging. Some white people seem to pick him out as being partially black right away. He’s also had the experience of having black people call him a “cracker” or otherwise indicate that they think he’s a (completely) white guy.
Genetically, I can’t guess how skin pigmentation is inherited and expressed - it might be that genetics for more melanin is dominant, but is affected by having a “less melanin” gene/group of genes/whatever and lightens up some in the process. But, I can at least say through observation that it is certainly not the case that the child of a black parent and a white parent will always have a dark or semi-dark skin tone.
For the societal definitions of race, see Cecil Adams on What percentage of black parentage do you need to be considered black?
IIRC there is no “skin color” gene , but a whole lot of genes that say either “Make melanin now!” or “Don’t bother with that whole melanin thing”. A kid’s genes will be a mix of whatever his parents had. Chances are if one parent is black and the other is white you will end up with something in the middle (although there is a chance that the child will inherit more of one parents skin color genes than the other).
I am not sure that it works the same for eyes and hair.
Skin color, like hair color, height, and many other traits, is determined by a combination of many different genes. It is not inherited in the simplistic Mendelian dominint/recessive manner that governs a few other traits. (And such traits are in the vast minority; even eye color, which is often taught as an example of dominance/recessiveness, is governed by the combination of several genes.)
The reason you think bi-racial kids are “black” is largely social. It is very likely that these children are in fact intermediate in skin color between their parents, but are classified as “black” because they are darker than most people of European ancestry.
My sister, who is white (Irish-German ancestry), is married to a black guy from Guyana. My neice and nephew have a skin color that is intermediate between that of their parents (often called “cafe au lait”). They are darker than their mother, but much lighter than their father. Likewise for some biracial celebrities, such as Derk Jeter and Mariah Carey.
Since a fairly large percentage of U.S. blacks have some European ancestry, it is likely that the offspring of an average U.S. white person and an average U.S. black person will be closer to that of a European than to that of a sub-Saharan African. However, due to the combination of the various genes that determine skin color and other traits, it is possible for the offspring to have a wide range of skin colors, etc.
I was going to reply with something I vaguely remember reading about Brazil where inter-racial marriage is IIRC fairly commonplace. The article talked about how skin color and the whatnot was migrating to a middle ground. So as Colbri and others say, perceiving the darker skin-color of the kid as “black” is social ('cause its very likely to be lighter than the other parent).
HOWEVER, when I did a quickie search to try and find that article (or something discussing the same), I found this article that compared skin color and other racial features (facial features and such) to actual DNA markers. They found NO CORRELATION between how someone looked and the ancestry of the person…in the long run anyhow. An interesting read, I thought.
Skin color is controlled by at least 7-10 genes, so it’s tough to predict. Kids can have a wide variety of skin colors depending on the genetic makeup of the parents.
Small anecdote: I am friends with a family with nine children. Father is black, mother is white. Some of the kids have dark skin, some have light. The older boys I wouldn’t think for a minute weren’t from a family with two dark skinned people but the younger girls aren’t dark at all.
Their hair (which is primarily of the black or very dark brown kinky curly type) is the only giveaway on the little ones.
I have two nephews who have a white mother and a black father. The boys are a beautiful cafe au lait color. When the boys were young, their parents divorced and their mother married a white man. The boys see their out-of-town father & his family maybe twice a year. So basically, they’ve been raised by white parents, surrounded by an extended white family, in a predominantly white neighborhood. When the older boy graduated from high school, he decided to go to a black college. I was stunned to find that both boys consider themselves to be black. Since race is a total non-issue within the family, I cannot begin to imagine how the boys came to think of themselves as black.
I know that the OP was concerned with physical color, but that seems to be far less culturally important than the perception of color.
… Looking forward to the day when it just doesn’t matter.
Up until a couple decades ago, in the enlightened state of Louisiana, one was legally “negro” if the percentage of african descended blood was 1/16th or greater.
I specifically recall a “60 Minutes” piece where they examined this standard. The best part was when they confronted an 80-something prim and proper (and no doubt racist) southern belle in her sitting room with the news that she was 1/16th negro and therefore legally a “colored person.” She was horrified, visibly shaken, as if the very firmament had been yanked out from underneath her. Nothing could have more clearly revealed the extent of her ingrained racism than her reaction to this news.
If someone told me I was 1/16th black, I would say, “huh… well perhaps that explains my preference for callipygian females.”
Actress Jennifer Beals, who is half black and half white, is generally perceived as “white”.
Indeed. Note the complexion, hair color & texture and eye color of actress Victoria Rowell’s 2 children: MahoganyCafe.com is for sale | HugeDomains
That is interesting, in NZ most people who are classified as Maori have white blood somewhere, even if it isn’t a parent or grandparent. I have noticed that in many cases, the Maori side is the one they identify with. This could be because the white side is not perceived as an identifiable ‘culture’ - not sure.