There they are. We can see two beautiful specimens, Homo sapiens, young people. You see, they are a little confused. It's not really surprising, of course. So what could happen at any moment now? The girl goes first. That's how would you be. She doesn't know what's happening to her. That's what it's like at puberty. A gland in her brain—the pituitary gland, produces hormones that make her grow. There's nothing you can do about that. Then she shoots at first, the hands and the feet. Take a look —she needs new shoes.

From now on, things start moving fast. Her breasts are now starting to grow. Ten years of age. Just image, the girl is now ahead of the boy, isn't she? Look at that boy. He doesn't have a clue what's going on. There he goes. While the girl's already starting to get pubic hair, the boy's only now embarking on puberty.

The girl races ahead—pubic hair and breasts sprouting. And she shoots up ahead. She's growing so fast that she can't keep up herself. She no longer has her body under control. That must hurt.

It's time the boy got himself some new shoes. He sees all kinds of things happening in his underpants. His testicles start to grow. At least, that's what happens first. After the testicles, the penis also gets larger. Sometimes he also has an erection just like that. It just happens. If we are lucky we can catch a glimpse of that. The girl is now in the middle of her growth spurt. After her arms and legs her torso starts to grow. And now it's the turn of her hips and buttocks. They all get broad. The bones grow and there's an increase in fatty tissue.

The boy now starts to get some pubic hair at last. And some hair starts growing under his arms. And now he starts losing control. It's all going too quickly for his proper left right left after all. And something funny starts happening to his neck. He develops an Adam's apple. That's also responsible for lowering his voice.