Gametes are the sex cells that are produced by the male and female of a species. Let us consider human beings as an example. Normal chromosome count in every human cell is 46 chromosomes, which are paired together in 23 homologous pairs. That 23rd pair of chromosomes is what is known as the "sex chromosome", the chromosome pair that genetically dictates whether you are male or female. In this chromosome pair is either an "xx" combination for female, or an "xy" combination for male. The gametes, or sex cells, are produced by a process known as meiosis, which halves the number of chromosomes. It also, in males, produces some sperm which have the x part of their sexual makeup, and some sperm that have the y part of their sexual makeup. The female egg only has the x part, since the female sexual makeup is xx. When a couple has sexual intercourse, the first sperm that reaches the egg establishes the sexual identity of the zygote. If the sperm is carrying the x chromosome, it will be female; if the sperm is carrying the y chromosome, the zygote will be male.
Human has 23 pairs of chromosomes in that 22 are autosomes and 1 pair is sex chromosome.
Sex chromosomes can be xx or xy.
If the individual has xx as the sex chromosomes pair then the individual is female.
If the individual has xy as the sex chromosomes pair then the individual is male.
female has two x chromosomes and male has only one x chromosome, and Y decide the sex of the individual.
Sex of a person is determine by the sex chromosomes. In human it is called as XX-XY sex determination.
a female has XX chromosome and a male has XY chrosomes. Y is the male determining factor for human sex determination.
During gamate formation, meosis occur which lead to reduction of chromosomes. in female it lead to the formation of only X containing gamate and in male one containing X and another Y.
Now during fertilization, the chances of fussion of these two games is
XX or XY that is there 50% probability of the offspring to be a male or a female. if it si XY it is male and if it XX then it is female.
So sex determination in human is determine by the sex chromosome of male (Y-chromosome)