Part 1: Hormones and puberty

We lovingly share knowledge, since #KnowledgeIsSuccess and the best way to take care of yourself and your partner is to have a good theory… Regardless of age. Dr. Arturo Valdés and Dr. Liliana de la Rosa, Creafam fertility experts, explain essential concepts of sexuality to us in an entertaining and easy-to-understand way.

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How about good afternoon, I am Dr. Arturo Valdés Carrillo and with me is Dr. Liliana de la Rosa, we are specialists in Gynecology and Obstetrics and experts in Reproductive Medicine and infertility from Creafam with almost 2 decades of experience in helping couples to fulfill your dream.

Lately we have noticed in consultation or talking with our own children and their friends that when talking about sex, people understand the “how” or “form” of things, that is, they know perfectly well that during adolescence, there are changes in the body, changes in the voice and that fat and muscle mass begin to settle in different parts, they also understand the mechanical issue of a sexual relationship.

But, sometimes we don’t very well understand the “why” of things, that is, the underlying reasons for hormonal function, or why some people find it difficult to get pregnant and others don’t, or even things as simple as what pregnancy means. semen color, variations in menstrual cycles and in general what things are physically normal and what things are no longer.

How is it possible that we all have manuals to know how our appliances or cars work and we don’t have a detailed guide on how our body works and what can go wrong?

That’s why we created this series so that teens (and parents) can better understand their sexuality and take care of their sexual health.

In fact, we give authorization to any educational institution and students to use this video, whether complete or in parts, remember that Knowledge Is Success.


Let’s start by talking about hormones. Hormones are the key to all sexual changes, even before birth.

Almost all of us know that the sex of a baby is determined from conception, the female egg has an X chromosome and the sperm has an X chromosome or a Y chromosome. The DNA of the future baby takes the mother’s o And from the father to define sex… However, at first it is impossible to distinguish whether an embryo is female or male.

It should be explained well that some people often say that we all start our lives as girls and that is why both men and women have nipples and that it is not until the pregnancy progresses that men begin to differentiate… However, the most recent studies seem to indicate that our body is actually a little loose and quite practical, so for the embryo it is not worth waiting for the testicles or ovaries to develop to know if it is going to be a boy or a girl, so to avoid problems from conception The nipples begin to develop and that’s how easy it is… If the baby is a woman, the nipples are ready! and if she ends up being a man, well… Actually, who cares if she has nipples? It doesn’t affect anything.

The embryo does not yet have a vagina or penis, it has something we call the “genital tubercle” and the gonads that will soon become its ovaries or testicles… Around week 5 of gestation, male hormones begin to act. What does this mean? When the baby is a man, the gonads begin to generate testicular hormones and then his genital tubercle begins to become a penis and testicles, and curiously in women this differentiation process still takes about a month to begin and is not until week 12 or 13. The vagina, uterus and ovaries begin to develop.

After all this explanation, surely many are thinking that this means that if we inject a female embryo with male hormones we could turn it into a man before being born… And well, no, it is not that simple, let’s remember that hormones are chemical messengers and all chemicals Our body’s messengers act only on certain receptors, if the gonads do not have male receptors, it does not matter how much testosterone there is, there will be no connection and there will be no masculinization.

Now… What are the male hormones and which are the female ones? To be exact, we cannot divide hormones into male and female, since biologically speaking, we all have a little of all types of hormones. The best way to classify hormones is to first divide them into steroid hormones and non-steroidal hormones.

Styroid hormones are derived from fats, specifically cholesterol, meaning that our body takes that fat and converts it into hormones. They are the best known hormones, since they are the ones produced by the testicles and ovaries, these are androgens and estrogens. Men have a higher amount of androgens and women have a higher amount of estrogens.

Meanwhile, in the brain or if we wanted to be more specific, non-steroidal hormones are produced in the hypothalamus, such as gonadotropin-releasing hormone, luteinizing hormone and follicle-stimulating hormone.

These last hormones are less known, but they are probably even more important since they are the ones that give the orders… The hypothalamus spends the first years of life lazy and almost doing nothing… But then around the age of 12 it wakes up and He gets to work. Although, if we want to be more exact, the hypothalamus begins to work around age 11 in women and until age 12 or 13 in men.

But as we have already seen… Sometimes our bodies are a little lazy or distracted and then everything works in a little chain that looks more or less like this and we can command or put it in a simpler diagram like this:

The hypothalamus produces gonadotropin-releasing hormone and this stimulates or turns on the pituitary gland, then the pituitary gland begins to secrete gonadotropins, which are nothing more than luteinizing hormone and follicle-stimulating hormone.

They are called gonadotropins and gonadotropin sounds like “Gonado Tripping” so you can learn what the hormones are that travel to the gonads.

Very good!

Once the gonadotropins reach the gonads, the testicles begin to release testosterone and produce sperm, however, the ovaries do not start producing eggs, women from birth have a certain number of oocytes and no longer produce more, they are all the ones they are going to have, but now that the ovary is receiving gonadotropins they begin to produce estrogens.

Exactly what happens when the testes and ovaries begin to produce androgens and estrogens? That’s right… Puberty is coming… But before fully entering puberty, we want to share with you that here is another interesting evidence of the action of hormones in the development of the fetus and it is in the ring finger.

Testosterone stimulates cell division, forming cartilage and bone for a longer finger. However, estrogen reduces cell division, resulting in shorter fingers. That is why women usually have the ring finger much shorter than the index finger, while men have it longer.

This does not mean that those with longer ring fingers have much more testosterone, or that they are more macho just because they have a longer finger. Something very interesting about hormones is that it is not about quantity but about balance. That is, it doesn’t matter if you have three times as much testosterone as another person, if you also have three times as many estrogens, the hormones practically cancel each other out, so a man could have a long ring finger not because of an excess of testosterone, but because of a lack. of estrogens.

So to close the chapter on hormones, we now know that there are no 100% male or 100% female hormones, there are only steroid hormones that are produced in the sexual organs and non-steroidal hormones that are released in the brain. Hormones are chemical messengers and although the amount of hormones is important, even more important is the hormonal balance and the presence or absence of receptors for any change to occur. Taking all this in mind now, if we can talk about puberty.


In general, most of us understand the changes that happen during puberty, there is a growth in height, women develop breasts and their first menstruation or menarche arrives, while men’s voices change, they become full of hair and increases muscle mass.

There are many discomforts that are almost inevitable… Yes, they are going to get acne, yes, they are going to start having intense body odor, yes, they are going to have sudden and intense mood swings and yes, they are going to start thinking about sex all the time. time, and no, don’t worry about masturbation, you are not going to become blind or infertile or stop growing from masturbating. However, in general, try to take good care of your hygiene, in all aspects, bathe daily, wash your face several times a day, brush your teeth well and make sure your genitals are clean, this will solve many problems.

As we had already mentioned, puberty arrives around 11 years of age in women and 12 years of age in men. However, puberty can be brought forward or delayed due to many factors, the main factor being genetic, if your parents are early or delayed puberty, it is very likely that the same thing will happen to you, but another very important factor, especially in women, is the level of body fat, remember… Styroid hormones are derivatives of fats, specifically cholesterol, that is, they Our body takes that fat and converts it into hormones…. So being overweight can help the body begin to produce estrogen and have the first menstruation at an earlier age, just as being underweight can also delay menarche.

For this video we are going to try to focus a little more on the things that are not so normal and that if they happen to them it would be worth talking to their parents and going to the doctor. For example, if puberty occurs before the age of 8 or still does not appear at the age of 14, it should be suspected that there is some type of syndrome, hormonal imbalance or even tumors in the sexual organs or the brain.

The man should have 2 testicles about 4 cm long and 2 or 3 cm wide, it is normal if one is slightly larger than the other and also for one to hang, so to speak, above the other… If there is another additional testicle, no It is normal, nor if one or both testicles are missing, it is possible that they have never descended and are inside the body, but you must go for a consultation.

The vulva of women should have a pair of labia minora, a pair of labia majora and the clitoris. It is normal for the labia to vary slightly in shape and size and to be a little asymmetrical, but if any of them are obviously different or there is an absence of some lips are not normal, in the same way it is normal for the breasts to be slightly asymmetrical.

The male and female sexual organs are very sensitive and it is normal for them to hurt slightly or feel intense tingling when touching them, however it is not normal to have intense pain that lasts all day, it is not normal to feel burning or pain when urinating.

It is normal for both the penis and the vagina to begin to produce a clear or perhaps slightly white liquid that serves as a lubricant. They can produce it with or without physical stimulation, what is not normal is for this liquid to have a bad smell, or to have spots of some color.


And well… With that we conclude the first video of this series, we try to explain in an entertaining way everything about hormones and the arrival of puberty, however there are surely many outstanding doubts out there, please write all your questions in the comments we will try to answer them in future videos or in your own comment.

See you in the next video which will be about menstrual cycles and semen. Knowledge is success.

“When talking about sexuality, without a doubt the best practice is a good theory”

Dra. Liliana de la Rosa Pérez
Dra. Liliana de la Rosa Pérez
Gynecology and Obstetrics

Reproductive Medicine Specialist
Universidad Autónoma de Barcelona

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