Ok. The two things as titles are confusing me. Both are the traits, right? And both were also influenced by genes.

 

But I don't understand what is their major difference.

 

Like colorblindness is an example of sex-linked while baldness is sex-influenced.

Sex-linked traits are said to be linked because more males (XY) develop these traits than females (XX). This is because the females have a second X gene to counteract the recessive trait. Thus, the trait is more likely to be visible in the male.

 

Sex-influenced traits are autosomal traits that are influenced by sex. If a male has one recessive allele, he will show that trait, but it will take two recessive for the female to show that same trait. One such gene is baldness.

a slightly clearer explanation of sex influenced from http://dorakmt.tripod.com/genetics/notes02.html

 

Sex-influenced dominance: A dominant expression that depends on the sex of the individual. An example is the horns in sheep (dominant in males, recessive in females). Another one is the plumage in domestic fowl: autosomal alleles whose expression is modified by sex hormones; the same genotype (hh) results in long, more curved and pointed plumage in cocks; shorter and more rounded in hens. Certain coat patterns in cattle, baldness patterns, breast development and facial hair (as well as all secondary sex characters) in humans are also sex-influenced traits. An autosomal dominant trait that controls precocious puberty is expressed in heterozygous males but not in heterozygous females. Affected males undergo puberty at 4 years of age or earlier. Heterozygous females are unaffected but pass this trait on to half of their sons (confusing the pattern with a sex-linked trait).