In a recent national study, only 15% of those born in 1940s had given or received oral sex by 1990s. In contrast, the majority of us who were born in 1970s had given or received oral sex when we got close to 40.

Oral sex was clearly a taboo to the 40s generation. Not as much a religious taboo or something related to upbringing, but more like a societal taboo. The adult population did not consider it acceptable for a guy to satisfy a woman with oral sex, since the man was supposed to be the one receiving pleasure (macho aspect). Average women, on the other hand, considered giving oral sex as something that only prostitutes and perverts did.

So, it was not strictly about upbringing but more like commonly formulated societal norm between adults. Why adults? Because there was hardly any sex ed in 1940s either at home or at school, so nobody told the 40s generation that oral sex was good or bad - it didn't exist! My generation (1970s), on the other hand, got decent sex ed both at home and at school, but still nobody talked about oral sex. However, when I hit my 20s the society in general was much more liberal, more porn was around and even mainstream tv showed soft core stuff emulating sexual techniques that were not discussed at all when the 40s generation grew up. In short, it was acceptable and there was no adult peer pressure against oral sex or sex in general.

Surprisingly, 25% of the women in 1940s generation approved of their spouse having a one-off extramarital affair. Amongst the today's 40-year old women that number was only 15%. So, the younger generation is not always more liberal.

Anyway, talking about sex openly is still psychologically awkward, albeit not shameful, because it signals that you are a sexual being, you like sex and maybe you would like to have sex with the person you're talking with. At least a male brain like mine works like that, no matter how educated or conscious of societal norms you are. If a woman talks to you about sex, you really can't help having brief images of her naked and having sex flashing through your mind. It's hardwired into our male brain and when this automatic response collides with the societal norms you've adopted, it makes you feel uncomfortable.