Today it is the glaring, unrestrained place of sex in the new Russia that is worrying the Kremlin and its educationists.
With the old social and state controls swept away, and a media now committed to as much sexual openness as in the more liberal Western European countries, children are said to be experimenting at a much earlier age.
Yet until now schools have not changed from the Soviet mind-set and have shunned sex education with the result, according to recent reports in the Russian media, that pupils have a "shockingly low sex IQ".
Now, however, the Russian education ministry is urging teachers to add sex education to their curriculum as a matter of urgency. It has launched a new programme entitled "Sex Education of Russian Pupils" specifically aimed at the classroom.
At the core of official concern are dramatic increases in teenage pregnancies, abortions and sexually-transmitted diseases, including Aids.
Last year nearly 220,000 girls aged 15 to 19 had abortions in Russia, according to the State Statistics Committee. The number for girls under 14 was 2,325.
Among the population as a whole, including adults, abortions now total some three million a year and are still regarded as a major form of contraception, as they were in Soviet times. By comparison, England and Wales have some 163,000 abortions a year (at the Russian rate, the equivalent would be around one million annually).
A total of 18 schools, including special schools, technical colleges and mixed-ability secondaries, in eight regions around Russia, including Moscow, St Petersburg and Krasnodarsk in Siberia, have been chosen for pilot projects which will begin in October 1997.
Attending sex education lessons will not be compulsory. Instead, schools will offer it as an optional extra in addition to the state and local curriculum.
It is based on work done by the World Health Organisation and aims to teach children the consequences of their actions. In addition, programme leader Tatyana Pestich wants to counter the contradictory information young people receive from the Russian media.
Organisers of a Moscow telephone hotline for teenagers welcomed the initiative, pointing out the low level of sexual understanding of many teenagers.
One 14-year-old girl was reported to have called recently to ask whether she could be pregnant after a session of heavy petting. A change from the past is that contraception is now more available, and more reliable, than in Soviet times.
Irina Simonova, 46, a Moscow mother, said that she had a succession of abortions because she was never taught about contraception and, when she found out about it, she could not obtain the pills.
"Today, still, schools do not yet teach anything much, the way you do in the West," she said. "But at least my 17-year-old daughter Xenia has access to more information and can obtain contraception when she needs it."
Milena Vradi, director of the hotline, complained that while awareness of the risks of unwanted pregnancy is greater among the young, there is ignorance in other areas. "Some know a bit about pregnancies but nothing about sexually-transmitted diseases," she told the English-language Moscow Times newspaper.
And even the switch by young Russians to using Western condoms - in the Cold War, Soviet-made sheaths were notoriously unreliable and the subject of many jokes - is not without its problems. Coloured Western brands are nowadays on sale in most Russian cities but teenagers treat these condoms "as a sign of luxury or wealth - not as a major way of self-protection", she added.
Recent polls of teenage sexual habits show that one in eight boys is sexually active by the age of 14, and one in 16 girls.
By the age of 16 half of boys and 30 per cent of girls have had sexual intercourse.
Almost one in three schoolgirls considers themselves victims of rape or sexual abuse - yet fewer than 10 per cent told their parents or the police.