question mark over genetics ?

do you know that for all the genetics in the world,it all boils down to a one in four chance between you and your partner? by all means correct me if im wrong its just what i have been told by leading specialists to the best of my knowledge.i cant get my head around it so any input other than these consultants would be truely appreciated
oooo fine
1000 fine
0001 fine
1100 not fine simple genetics,anybody else understand this?

[eureka254]

Genetics is much more complex than boiling it down to "one in four chance."  That particular phrase is used most often in the context of what's known as "recessive" genes, but that is only a very small part of genetics.  The risk of 1 in 4 associated with recessive conditions does not apply to many other genetic patterns. Different genetic conditions exist, and many of them do not follow the rules of recessive inheritance.

"Recessive" in genetics refers to a condition that is usually benign in a "carrier."  The 'you and your partner' part with recessive conditions depends on the fact that we each get half our genes from our mother and half our genes from our father.  So, for example, you are a female, and you one set of X chromosomes (where genes are located) from your dad, and the other set of X chromosome from your mom.  (The *normal* female pattern is XX; men get their "X" set from mom and their "Y" set from dad.)

Now, mom's chromosomes have thousands of genes and and strands of DNA just like dad's does.  However, when eggs and sperm are made, they aren't full human cells, 46,XX, or 46,XY.  Instead, eggs and sperm are haploid, or half of that: eggs are 23,XX and sperm are 23,XX (make baby girls) or 23,XY (make baby boys).  That's where the 1/4 chance happens, because depending on the combination of egg/sperm, recessive genes can express.

You can find a useful chart and explanation of how recessive inheritance works here:
http://anthro.palomar.edu/mendel/mendel_2.htm

Remember, however, recessive conditions are but a small fraction of genetic diseases that exist.  Hope that helps answer your question some.  ~eureka

[eureka254]

I should add, recessive conditions are not always harmful.  For example, having O blood is a recessive condition.  People who are albino are recessive for skin pigment.  A visual of how that works:  
http://library.kiwix.org:4201/I/300px_Punnett_square_mendel_flowers_svg.png