In human beings the new one is born sexually. 
a human male has  23 pair of chromosomes from which 22 are autosomes n 1 is of sex determination . it consists of longer X n shorter Y chromosome. a human female has 23 pair of chromosome out of which 22 are autosomes and 1 is of sex determination . female has x x chromosomes. the child inherit x chromosomes from father then it will be daughter if child inherit y chromosome from father then it will be a son . thus the chances are 50 % to be a male or female.