"The Talk". That's how many teenagers refer to a unique moment, a moment that we all have to pass, and so intense and embarrassing a moment that you wish you had never been born. Ironically, that's the subject discussed on "The Talk": the birth of human beings. "The Talk" is that specific hour when your father comes to you and uses all kinds of metaphors possible just to illustrate how the human reproduction occurs. Of course, when this moment arrives practically all the teenagers already know what it is like. After all, sexual reproduction is not so complicated. Or is it?

Sexual reproduction is just the formation of a new individual following the union of the parents' DNA. As a result, that individual will be genetically different from both of his or her parents. That happens because the gametes (germinative cells) come from two sources: one male (the spermatozoid) and one female (the egg). Each one of them bears half the amount of a regular cell's chromosomes. That way, when combining, they form a completely new individual different from the two sources. So, both man and woman have to do their part in order to generate a baby. The man's role is easier: he has the spermatozoids and just has to find the means necessary to deploy them inside the woman's reproductive organ. That's where sex comes into play. Once his penis is inside his partner's sexual organ by doing so reaches an orgasm, his spermatozoids will be released. Then, it's only a matter of time: when one of the spermatozoids finds the egg and fecundates it, the man's role is over. Now, the ball is on her court.

And her role gets rather complicated. First, her physiology manufactures eggs, action that takes place in the ovaries. Then, she needs to be prepared to receive his sperm, and such preparation is a phenomenon called "ovulation", which occurs about two weeks after the onset of menstruation. It's when her gamete moves slowly down the fallopian tube. To achieve fertilization, sperm must be deposited in the vagina within a few days before or a day or two after ovulation. Once done, comes the next phase: her uterus must be ready to shelter a baby. She ought to feed the developing baby while it's becoming an individual. After childbirth itself is over, she will keep feeding the baby for time being through breast-feeding.

As you see, there's nothing complicated about sexual reproduction. A natural event that takes place by natural ways. Tell that to your father next time he tries do run "The Talk".