Conference moira::parenting_v3

    I was concerned about the passing on of the gene that causes color
    blindness because my husband is color blind.  I was told (can't
    remember where) that it is the female that carries the gene and passes
    it on.  Anybody else out there heard this??

    There are several different kinds of colorblindness, but the most
    common kind is sex-linked: the gene for it is on the X chromosome
    (if my memory serves me correctly here).
    
    If you're worried, most medical places will have a set of the spot
    diagrams used to check colorblindness.  Some well-equipped eye-glass
    shops have them as well, as might nurses' offices in DEC plants and
    schools.  Whether your son is old enough to respond to the diagrams
    depends a lot on how good he is at numbers and how well he follows
    directions.
    			-John Bishop

    I have wondered about the same thing with my son.  My grandfather is
    colorblind as is my cousin, Scott.  I heard that the women is the
    carrier and was also wondering at what age I would be able to find out
    if he is colorblind.
    
    Kathy

re: .0

Does your son have trouble identifying ALL colors, or just certain ones?  Does 
he misidentify colors or does he have trouble remembering the "name" of the 
color?

Someone else out there correct me if I'm wrong, but I believe color blind 
people have trouble only with certain combinations of colors.  If he has 
trouble with all colors, or can't remember the name of a color, it could very 
well be something other than color-blindedness.  I don't find a child of three 
who hasn't learned colors yet to be particularly unusual, particularly if he 
is closer to two than to four.

Clay

    * Anecdote alert *
    
    I once had a housemate who was completely colorblind - his whole
    world was black, white and gray. If he saw a single flashing traffic
    light, he had to guess from the behavior of other cars what color
    the light was - he had no clue otherwise. (And in Somerville MA,
    the behavior of other cars didn't necessarily help, either.)
    
    This poor guy had a heck of a time choosing clothes. He asked friends 
    to shop with him, and he would always ask one of us housemates to look
    him over before he left the house in case he was wearing some awful
    combination. I always felt sorry for him, missing out on colors.
    
    Lucy

    It is not at all uncommon for children to be slow about developing
    a sense of colour.  Actually colour is an extremely difficult concept
    to grasp because it is the quality of an object, and not the object
    itself.  Three is a normal age to start to develop colour awareness.
    
    For our eldest, for the longest time any favourite colour was always
    pink.  She associated nice things with being pink.  As it turns out
    she is now very colour sensitive.  Our youngest (4 tomorrow) only
    developed colour sense about Christmas time and now loves colour.
    
    I wouldn't worry about this for a while yet.
    
    Stuart
    

    There is another level - color confusion. I know it sounds weird - but
    I have it. Shades and combinations of red, blue and white *confuse* me. I
    can see color - just don't mix it up. Never even knew, until I was
    eighteen and the Army rejected me as a pilot candidate after extensive
    tests. 
    FWIW
    JR

    Here's what I know of color-blindness genetics.  The gene is 
    recessive and carried on the X chromosome, so men can only inherit 
    it from their mothers.  Women CAN be color-blind, but only if both 
    of their X chromosomes carry the gene.
    
    If I call a regular X chromosome "X" and a color-blind one "Xc", I 
    can make up a chart for you.  My assumptions are that neither you 
    nor your husband is color-blind; I'm also assuming for simplicity 
    that your Mom isn't a carrier.
    
    
    			      Your Mom
    			      X	      X
    			  -----------------
    		  	  |  	  |  	  |
    		  Y	  |  XY	  |  XY	  |  <-- your brothers, if any
    		  	  |  	  |  	  |
    Your Dad	  	  -----------------
    		  	  |  	  |  	  |
    		  Xc	  |  XXc  |  XXc  |  <-- YOU are absolutely
    		  	  |  	  |  	  |      a carrier!
    		  	  -----------------
    
    
    		  	        YOU 
    		  	     X	     Xc
    		  	  -----------------
    		  	  |  	  |  	  |
    		  Y	  |  XY	  |  XcY  |  <-- Your SON has 50-50
    		  	  |  	  |  	  |      chance of being C-B
    Your husband  	  -----------------
    		  	  |  	  |  	  |
    		  X	  |  XX	  |  XXc  |  <-- Your DAUGHTERS have
    		  	  |  	  |  	  |      a 50-50 chance of
    		  	  -----------------      being carriers
    
    
    I know there are degrees of color-blindness, and I don't know what 
    determines the "severity."  My uncle cannot tell red from green 
    (apparently they both look to him the way grey looks to us); 
    another relative just has trouble in dim light distinguishing 
    between magenta and red-orange, or between teal and royal blue.  I 
    have an aquaintance who sees only black & white (& grey), so he 
    dresses in only black & white so he'll be seen as he sees himself 
    (of course, he has to trust the store clerk and his shopping 
    companions to give him no colors)!
    
    Leslie-who-may-be-a-carrier-and-whose-daughter-definitely-is

    I'm probably (very) confused, but here goes...according to
    what Leslie says, if my father is color blind, am I automatically
    a carrier?  Or are my chances of being a carrier just greater
    than someone without a colorblind father.
    
    I have a son, what does this mean for his chances of being
    colorblind?  He's only 17 mos old now, so everything to him
    is "Yellow"
    
    thanks, 
    Linda

    .0 and .9 - John Bishop in .2 indicates that there are some non-
    sex-linked kinds of colorblindness, and I don't know the cause or the
    rarity of those kinds.  So I shouldn't have said to Joanne "You are
    *absolutely* a carrier" unless I also said "IF this is the sex-linked
    kind."
    
    Linda, if your Dad's is the sex-linked kind, then the recessive gene is
    on his X chromosome, and since you're a girl  :-D  you have his "Xc" as
    well as one of your Mom's Xes.  Same profile as Joanne's.
    
    Anybody out there heard any more about the non-X-linked C-B?
    
    L.W.

    Thanks Leslie,  I forgot that the base noter was in the same
    situation...that makes things clearer.
    
    Linda

    re .10, and others:
    
    There have been articles on the various color-blindnesses in
    Scientific American and the like.  I'm sure a reference
    librarian could help you find more information.  What follows
    is from memory, based on my reading over a number of years. It
    is also simplified, due to my not wanting to write a multi-page
    note!
    
    There are three pigments in the eye which sense color.  If
    you lack any one of them (i.e. have only two), you lose some
    colors, but not all--this gives three different kinds of 
    single-loss color-blindness.  If you lack two pigments, you
    lose almost all color sense (but I think you retain some based
    on the different frequency response of rods and codes...),
    and there are three different kinds of double-loss color-blindness.
    I suspect you can loose all three and still retain rod-based vision,
    which would make yet another kind--but you'd also lose vision
    completely in the parts of the retina with cones, so it'd be
    just plain blindness rather than color-blindness.
    
    Howver the loss of pigment can be partial, which means more than
    one degree of each kind of color-blindness.
    
    Only the "red-green" kind is anywhere near common, and it's the 
    one which I am sure is sex-linked; the others may be, or they
    may not be--I just don't know.
    
    In any case, a 17-month-old who knows even one color name is doing
    well--my 18-month-old son has no interest in colors at all, as far
    as I can tell, and isn't even consistent about "Mommy" and "Daddy"!
    
    			-John Bishop

    See also DECWET::PHYSICS, note 160.*, about color and vision.
    
    		-John Bishop

    I remember seeing something on PBS a couple years ago about a recent
    study about colour, and from what I can remember there are now
    dubious about the idea of the three colour light sensitivity
    theory because of the ability to still distinguish the correct
    colours when the clour information is distorted.  For example,
    take a multi colour scene, cover the scene with a colour filter
    and you can still identify the original colours.  Weird.
    
    One theory was that contrast played a great role in colour
    sensitivity, and the relative frequency differences between the
    colours.  In a simplified model, it is rather like colour tv
    is actually transmitted.  While the colour of a picture is
    made up of Red Green and Blue signals, what is actually transmitted
    is Red, Green and a signal called Luminance which is essentially
    brightness, and provides for the compatibility with black and white
    tv.   The blue signal is recreated by taking the luminance signal
    and subtracting R & G from it in the correct proportions.
    
    So, unfortunately it would seem that it is still unclear how colour
    vision actually works, and thus how colour blindness occurs.
    
    Stuart

>    					Our youngest (4 tomorrow) only
>    developed colour sense about Christmas time and now loves colour.
    
    I must be losing it ....
    
    I invented an extra year for my youngest ... she was *3* yesterday
    not 4 !  
    
    But still, some children are slow at grasping the concept of colour,
    and some are also slow at learning colour discrimination.
    
    Since, even if he is colour blind there isn't anything you can
    really do, apart from show patience and understanding, I wouldn't
    worry too much until about 3 1/2, then have it checked out.  That
    way you can prepare school teachers well ahead.
    
    Stuart

    First, thanks to all the scientific theories for colorblindness, I had
    no idea it was that involved.
    
    Now in my situation I have a problem distinguising some green and
    blues, unless they're side by side.  We'll see if AJ has inherited that
    from me, since I know I inherited it from my paternal grandmother.
    
    When he was a little over 2 I questioned if he was seeing colors
    properly, so I conducted a little "home survey" over the course of a
    day or two.  When we were at the fire station, which he sees several
    times a week thanks to dad and mom working for them part time, I
    casually asked what color the various fire trucks and the ambulances
    were.  He got each color right.  I'm not going to argue on the
    yellow/green color everyone is doing trucks lately, I'm not really sure
    if it's really yellow or green. (By the way that color was invented
    *for* colorblind people, since they freqently can't see red, but this
    color has been determined it can be seen by colorblind people) He was
    able to identify the orange and white of the ambulance, and the things
    inside which are red, blue, green and a variety of colors.  As we left
    the station and headed for the center of town I stopped at a red light,
    and asked what color it was, and then what color it was when I could
    go.  He got both of those right too.  Maybe not scientific, but at
    least a little reasuring.  You could try it with familiar things in
    your neighborhood.
    
    On another case, my son's godfather is quite colorblind.  His very
    understanding and quite organized wife has arranged his clothes in one
    color per drawer, or perhaps two colors per drawer; one per side, and
    labeled the drawers with colors.  By the way, this man was a
    firefighter/EMT for many years and now is in management for a hazardous
    waste company.  Of course hauling hazardous waste requires plaqcarding
    trucks with colored indicator cards, but fortunately they also have a
    Dept of Transportation reference number too.
    
    Lyn