Yes, folks, I'm talking about the 50s. Actually it was probably a bit patchy before then, but compared to the halcyon times to follow, it was a sparse period indeed.

Interestingly enough, these new and rather disgusting theories did not displace the prevailing theory, that one prayed for babies. In fact one of the polls we took on a regular basis was who would use which method. Most of us decided that we would pray for babies when it was time, and looked askance at those who professed otherwise.
The mother of a friend must have had an eroded cervix, because we were assured by him that after his parents had "done it" there was blood on a towel. We were horrified, and I don't think any of us looked at our obviously brutish fathers in quite the same way again. Though of course almost all of us were convinced that none of our parents were doing it any more. I mean, why bother after the birth of the last sibling? I think we felt very sorry for any child whose parents were sufficiently depraved to continue such practices after the necessity had passed.
Literature was of little help either. There were only three sources that I knew of.

The second was an infamous book called "What Every Young Boy Should Know". Despite the title, it was a deeply unhelpful book and scarred most of us for life. I think it was published late 19th century but was still doing the rounds when I was a lad. To cut a long story short, we were to avoid, at all costs, a self-stimulating activity that would lead to a "spasm of the nerves" which would surely result in imbecility, madness or even death. From the same source I learnt that a drop of semen was worth a pint of blood. No wonder I'm so anaemic.
The last was "Ideal Marriage" by van de Velde. This wasn't such a bad book in fact, just constrained by the times. In those days books couldn't extol the "joy of sex" directly; they were required to take the form of text books of the medical genre. It thus featured some details you would rather not know, but also an intriguing illustration of a woman with three pairs of breasts. Apparently we have a "milk line" as other mammals do (such as cats and dogs) and while more than one pair along the line is unusual, it is not impossible.
By the time I got to university and was doing psychology I was able to buy such books openly (I have to admit buying van de Velde mail order when I was 17 - far too embarrassed to do so across the counter).
And thus a new world opened to me, the world of sexology. First, an important aside, the phenomenon of self-selection. Why are people drawn to (that is self select) certain professions? To be a surgeon, minister, psychologist, whatever? And what the heck are the self-selection dynamics for sexologists?
Consider for example Havelock Ellis, one of the first well known sexologists, who was breaking the mold back in the late 19th century. Difficult times. A bookseller was prosecuted in 1897 simply for stocking a book he had co-authored on homosexuality.
In many ways Ellis seemed more like a candidate for treatment than one to administer it. He married Edith Lees, a writer, in 1891. He was 32 and still a virgin. She was a professed and openly practising lesbian. After their honeymoon, he went back to his bachelor pad, and she stayed where she was. He was also impotent his whole life, but that changed when he was 60 when he discovered that he was sexually aroused by the sight of a woman urinating. There was a possible link with his childhood. His devoted, yet clearly insane mother, used to slap him playfully in the face with his wet nappies.
Slightly predating Ellis was Richard Freiherr von Krafft-Ebing, an Austro-German sexologist and psychiatrist. He wrote Psychopathia Sexualis (1886). This documented different forms of sexual perversion that he had encountered. I read parts of this as a student, and the juiciest bits were in Latin. This was not so in the first edition, but its fame was so widespread that "ordinary people" began to buy it. It was to protect them (and me, alas) that the Latin was instituted.
Although it may not sound like a fun book, and to be honest it wasn't, a lot of people benefited. If you were a shoe fetishist in the 19th century, you probably thought you were the only one on the planet. It was of genuine benefit to people like that to realise they were not alone.
Enter Kinsey. Alfred Kinsey is generally regarded as the father of sexology, and immortalised in the Kinsey Reports starting with the publication of Sexual Behavior in the Human Male in 1948, followed in 1953 by Sexual Behavior in the Human Female. According to some authorities these are still the bestselling scientific books of all time. Curiously enough, before sex, his scientific interest had been focused on the Gall Wasp.
These studies were statistical - and we were to learn, as never before, who did what to whom and how often.
Less well known was that Kinsey (it has been rumoured) participated in unusual sexual practices, including bisexual experiences and masochism. He encouraged group sex involving his graduate students, wife and staff. Kinsey filmed these sexual acts in the attic of his home as part of his "research".

But, as with all the others, good things came from it. They established inter alia that older people did have sex, that there was no difference between vaginal and clitoral orgasm, that there were clear stages to sexual arousal and probably did more than anyone else to establish workable sexual therapies.
So there you have it. In one lifetime (mine) we have gone from woeful ignorance to more sexual information than you can shake a stick at. In fact there is probably more sexual knowledge in one issue of Cosmo than in my university library when I was an undergraduate.
Has it helped? Without doubt. Has it done harm? Without doubt.
Oh, and in case you're wondering, I never did become a sexologist. It was all just prurient curiosity. My speciality was visual perception. Ho hum.