It threatens human life and dignity at every stage: Birth control. Abortifacients. Abortion on demand. Fetal-body-parts trafficking. Pornography. Slavery. Suicide. Assisted suicide. Euthanasia.

If you prefer a more liberal view: Human trafficking. Child labor. Pollution. Exploitation of the poor. Banning labor organizing Totalitarian and authoritarian government systems.

Basically, sin with no fear of consequences.

While our understanding of these teachings has changed, the core teachings have not, so for my money I will go with church teachings more than psychologists if there is a contradiction.

But the Catholic Church insists that there can be no conflict between science and religion. Also, the Catholic Church has no body of teaching that I know of that could be called "Catholic psychology." The Catholic Church may call homosexuality "disordered," but that is quite different from calling it a "mental disorder." Does that Catholic Church have any teaching about ADHD? Is it for or against drugs for ADHD? As far as I know, the Church leaves it up to psychologists and psychiatrists. So I don't know where you are going to find "Catholic psychology."

The psychologests flip flop every few years. Back in the '70's homosexuality was considered a mental disorder. Today they say it is normal. It used to be that a child was just nerdy, now psychologests tell us they have autism. Fifty years ago a child might be "restless" so they would give them an extra P.E. class to calm them down. Today they are told they have ADD a disorder and are given harsh medication. What was normal is now a disorder and what was a disorder is called normal.
The Catholic church has had the same basic teachings for two thousand years. While our understanding of these teachings has changed, the core teachings have not, so for my money I will go with church teachings more than psychologists if there is a contradiction.

I hear what you're saying, but whereas they say war it too important to be left to the generals, I can't see to whom psychology can be left other than the psychologists!

It is not uncommon for out-of-date information to survive in textbooks for quite some time after it has been contradicted by newer research. This is true not just in psychology.

The biggest problem I have with psycology is that years after Dr Money's study was shown to be false the psycological comunity continued to teach it as true. By 1980 the study proved the exact opposite, yet thatfact was held in the dark. I took psycology in 1991 and we were still learning it as true. He had to come out on Opera to make.them.stop teaching this.stuff. After i saw him on Opera i asked a friend who was a few years younger than me who was getting her Phd in psycology, what she thought of the case. She looked ar me with a blank look and said she had never heard of it. An instition who is not only wrong, but continued to teach and propigate a lie has no credability with me. Not only that, but once the lie was discovered they erased it from history.

Psychology, psychiatry, neuroscience, and so on, are all in their infancy. There is an amazing amount yet to be discovered. If every science got everything right the first time, we would already know everything knowable.

I am currently reading a book on cosmology (The Goldilocks Enigma: Why Is the Universe Just Right for Life? by Paul Davies), and most of the story takes place within my lifetime (1964, Penzias and Wilson detect the background radiation from the Big Bang). Watson and Crick discovered the structure of DNA when I was in elementary school. There has been a tremendous advance in knowledge in my lifetime, and yet in many respects, humanity has just scratched the surface. It should be no surprise when it turns out something that once was believed turns out to be not as solid as it once was, or even that the opposite is true. This is especially true of nutrition, which seems to have about one reversal per day if you read the newspapers. How many people at margarine for years because butter was allegedly bad for you, and then it turned out trans fats are much worse. How many of us switched from whole milk to skim milk to avoid the fat, only to read a few days ago that people who drink whole milk live longer? The optimal amount of exercise you are supposed to get changes every day, it seems.

Everything is changing all the time, but if we don't trust psychologists to know psychology, whom do we turn to?

Touching on David Nickol's point, sexual orientation is strongly genetically influenced - it manifests in a stable way, and is highly resistant to any environmental effort to alter it. The person may learn to behave in a way inconsistent with the orientation, but that does not alter the attraction to the same sex or the lack of attraction to the opposite sex (which is not always either-or, but may exist on a continuum). A few decades ago, when homosexuality was still considered a mental illness, a number of therapeutic approaches were developed to try and "correct" the orientation. None of them worked, and many could be harmful, to the point that it is now unethical to try them. Even a direct environmental intervention following the most effective methods to alter thoughts, emotions and behavior were not able to have an effect, because sexual orientation is primarily genetic.

It is important to distinguish what the predominant view within the field of psychology is and what the media presents the predominant view as. The idea that nurture plays the only role in shaping behavior came out of strong behaviorism, which reached its peak in the 50s and was in decline by the 70s, and is now recognized as a discredited view, although many principles discovered within behaviorism are valid. Two of the students of B. F. Skinner, a central figure in promoting strong behaviorism at the time, identified instinctive drift, which is when a learned behavior is overtaking by instinctive actions.

The importance of genetics was recognized within the field even at the time, but separating the influence of genetics and environment is more difficult. Some of the best data comes from studies of identical twins who were raised apart. Others come from traits that are identifiable early on and are stable despite environmental changes. At this point, we are able to actually test DNA and look more closely at genetic markers, but there is still a lot more to learn, which will further clarify the role of genetics and environment.

In terms of gender, some qualities have a genetic base - girls are more often verbal and social earlier than boys, boys tend to be more physical and aggressive. The between group differences, however, are not greater than the within group differences. In addition, there are also many social factors that shape the specific expression of gender, such as expectations of how to act due to a person's sex.

To bring this back to your comment, the scientific community as a whole does not accept either that environment or genetics define gender identity, but rather that both play an important role. Those who argue for either pure genetics or pure environment are not expressing the consensus. However, many such people are actually referring to a specific factor within gender identity that is predominantly shaped by genetics or learning, not gender identity as a whole. How the media represents this, however, is prone to misunderstandings.

Up untill the '90's the scientific community was telling us just the opposite about gender identity. The prevaling view was that if you raised some one as a girl they would become a girl. If you raised them as a boy they would become a boy. Now those same people are telling us that gender identity has mothing to do with how they were raised, that there is something innate inside them that does not corrispond to phisical gender or how they were raised. Psychlogests have very little credibility with me. https://en.m.wikipedia.org/wiki/David_Reimer

What if it is the case, and there are at least some indications that it's true, that a transexual with a male body has a "female" brain, and a transexual with a female body has a "male" brain. Do you think that this is utterly impossible?

Say it is the case that the brain is not in conformity with the body. Why should someone with a female brain not identify as a female, in spite of male external genitalia?