There are a total of 23 pairs of chromosomes or 46 total chromosomes. All of the body's genes are contained within these 46 chromosomes. Females have 2 X chromosomes and males have 1 X and 1 Y chromosome. The Y chromosome determines the male sex but does little else.
Chromosomes exist in pairs.
For convenience, scientists have numbered the autosomal chromosome pairs 1 through 22. The X and Y chromosome are the 23rd pair. Therefore, it is the male that determines the sex of the child.