The male reproductive system is responsible for providing half of a new baby's genetic material. In doing this, the man must produce millions of healthy sperm, only one of which will be successful in fertilising an egg at conception. About half of a man's sperm carry the gene to form a girl baby (known as the X chromosome) and the other half of the sperm carry the gene to form a boy baby (known as the Y chromosome). Therefore, it is the man that determines the sex of each child.
The following provides an overview of the male reproductive system. We will first describe the man's external genitals before explaining his internal reproductive organs.
Man's external genitals
Man's internal reproductive organs
Man's external genitals
The man's external genitals generally consist of his penis and scrotum (which contain the testes) and are explained as follows:
The penis
The scrotum
The penis. The penis is formed from three cylindrical columns of erectile tissue. This erectile tissue is a spongy network of connective tissue and smooth muscle, full of small spaces, each about the size of a pinhead. The penis usually lies flaccid in front of the scrotum, but when the man is sexually aroused (or the penis is stimulated) nerves to the penis cause blood to fill the many vascular spaces in the spongy erectile tissue, so that the penis is engorged with blood. This enlarges the penis and makes it erect for intercourse with the woman.
The end of the penis (or head) is called the 'glans'. The glans is supplied with many sensory nerves and is the most erotically sensitive part of the male genital area, producing sexual enjoyment. The male glans is the equivalent to the female
clitoris, being formed in the womb from the same type of erectile tissue.
The glans forms a smooth protective cap over the end of the columns of spongy tissue in the penis and has an opening at the tip called the urethral meatus.