Answer to Question 1
As the names imply, these conditions occur when a normal ovum is fertilized by a sperm that has two Y chromosomes or two X chromosomes, or when an ovum with two X chromosomes is fertilized by a normal X sperm. The XYY individual may grow up as a normal male and the XXX as a normal female, and so often their unusual genetic status is not detected. However, many do suffer from some genital abnormalities, fertility problems, and possible learning difficulties later in life.
Answer to Question 2
The testicles produce androgens, which are quite important to the male, because even a genetically male embryo will develop in a female direction if androgens are not secreted at the right time or if the fetus is insensitive to androgens.
