Teen dreams: Facts of life - text only -

• Girls

• Boys

• Both

• Girls
• Before puberty, girls have about 500,000 follicles containing immature eggs in their ovaries.

• When eggs mature inside follicles, the follicle swells to more than 100 times its original size.

• The average woman produces nearly 500 mature eggs during 40 years of fertility.

• The largest cell in the human body is the female ovum or egg cell. It is about 0.14mm in diameter. The smallest cell in the human body is the male sperm. A single egg cell weighs as much as 175,000 sperm cells.

• Boys
• A boy's skeleton can grow at a rate of up to 1cm a month during puberty.

• The penis is the fastest-growing part of the body during puberty — if the rest of the body grew at the same rate, adults would be over 2.74m tall.

• Adult testes produce 1000 sperm per second at their peak.

• During an erection, a penis swells to five times its normal size.

• Boys can have as many as 20 reflex erections a day during puberty.

• Most men have erections four or five times a night during sleep.

• There are 100 million sperm in every ejaculation.

• The average human sperm travels 17.8cm in its lifetime at a rate of 0.016kph.

• According to the Kinsey Institute, the biggest erect penis on record measured 33.03cm. The smallest was 4.45cm.

• Both
• Human hair normally grows at the rate of 15.24cm per year.

• When you begin to grow pubic hair you can grow as much as 20m of it in a month.

• Beard hair is the fastest-growing on the human body. If the average man never trimmed his beard, it would grow to nearly 9.14m long in his lifetime.

• The body has two million sweat glands.

• Armpit glands can produce up to 11.3 litres of sweat in 24 hours.

• A hairy armpit can hold 30 times more sweat than a hairless one.

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