Why is a sex-linked trait rarely (if ever) seen in the opposite sex from the expected sex type?

Sex linked traits are traits controlled by genes located on either the X or Y chromosome.

Why is a sex-linked trait rarely (if ever) seen in the opposite sex from the expected sex type?
because if its y linked then women can't have it because women don't have a Y chromosome while if its X linked it is usually recessive so males don't have a dominate allele to counteract it so the recessive shows through and to have two X recessive alleles in one cell is very rare because the male has to have the recessive phenotype and the female has to have a heterozygous genotype. Sorry for the in depth language.
Reply:Well, with Hemophilia, it only shows up with an X and a Y....some women are XXYs and have hemophilia, but it's very rare....same thing happens with men who get women's diseases....they have an extra X chromisome.
Reply:Sex linked traits are inherited on the X chromosome, thus men tend to display these traits much more often. Men only have one X chromosome and one Y chromosome, thus, whatever sex liked traits are carried on that X WILL be displayed in that male individual. Women are less likely to display the sex-linked characteristic because they inherit two X chromosomes. Because of this, the characteristic may or may not be displayed depending on whether it is a dominant trait or recessive trait.





Because of this, if a male displays a sex-linked trait, it may not show up in his female offspring, especially if it is a recessive trait and his wife is homozygous dominant.





Hemophilia is an example of a sex linked trait, as is colorblindness and male-pattern baldness. While men are commonly colorblind, females are rarely so. Also, male-pattern baldness will always be the fault of the mother. Males cannot contribute at all to male-pattern baldness because obviously they can only contribute the Y chromosome. The female is then the only source of X chromosomes, thus if male-pattern baldness runs in your family, never blame your father.
Reply:Sex linked traits can usually only be expressed in the sex that has only one of that chromosome. Since females have two X chromosomes, I don't think you could say that a female has any sex linked traits.





The male can have sex linked traits from his father's Y or his mother's X chromosome.