Question

in a human dna sample, you detect dna that is specifically from the x chromosome. why are you unable to definitively determine the sex of that person (male or female) from the presence of the x chromosome?
both males and females have an x chromosome so you would also have to evaluate the autosomes to determine sex.
x chromosomes do not determine gender so you would have to have additional dna analysis.
males and females have different types of x chromosomes, so you would have to know which specific x chromosome was detected.
both males and females have an x chromosome, and you would have to check for the presence of a y chromosome.

Explanation:

In humans, females have two X - chromosomes (XX) and males have one X and one Y - chromosome (XY). So, the presence of an X - chromosome alone is not sufficient to determine sex as both genders have it. One must check for the presence of a Y - chromosome to definitively determine sex.

Answer:

Both males and females have an X chromosome, and you would have to check for the presence of a Y chromosome.