We are appraoching the 100-year anniversary of Hollywood sex: Theda Bara’s incarnation as The Vamp in A Fool There Was (1915), a lurid femme fatale who slew overnight the lingering Victorian ideal of the pure, saintly woman-child, portrayed on screen by Mary Pickford and Dorothy and Lilian Gish. Theda Bara, like Lady Gaga, was a manufactured personality; although the studio publicity department claimed she was born in the Sahara to a French artist and Arabian princess, she was actually Theodosia Goodman, the daughter of a Jewish tailor in Cincinatti.

The sexual icon of 1920s Hollywood was Clara Bow, a madcap flapper who was probably falsely rumoured to have bedded the entire University of Southern California football team. Lithe Louise Brooks, with her signature bobbed hair, made landmark films of decadent eroticism in Germany. Wicked mae West and lushly buxom Jean harlow began the tradition of the sex bomb, which continued through Hedy Lamarr to Jane Russell and Marilyn Monroe, whose influence endures around the globe. But the cardinal sexual pioneer was Marlene Dietrich, who exploded on the international scene in 1930 as the heartless cabaret singer of The Blue Angel. In her subsequent films with the director Josef von Sternberg, Marlene toyed with transvestism (based on the drag balls of Weimar Berlin) and created the sophisticated look of hard glamour that remains a staple of fashion magazines.

Marlene was Madonna Louise Ciccione’s idol; the seductive, commanding Marlene permeates Madonna’s brilliant videos of the 1980s and the early ’90s, with their dominatrix, transvestite and bisexual motifs. Madonna wanted to play Marlene on film, but the idea was overruled by Marlene herself, who (as the proud daughter of a Prussian officer) decreed Madonna “too vulgar.”

Weimar cabaret was recreated in the 1972 film Cabaret, based on Christpher Isherwood’s Berlin stories. Bob Fosse’s dazzlingly aggressive choreography in that blockbuster film was adopted by Madonna for her videos and stage shows - all of which have been doggedly imitated by Lady Gaga. Gaga has borrowed so heavily from Madonna (as in her latest Alejandro video) that it must be asked, at what point does homage become theft? But the main point is that the young Madonna was on fire. She was indeed the imperious Marlene Dietrich’s true heir. Madonna’s incandescence is still on view in videos like Open Your Heart, Vogue and Express Yourself. However, for Gaga, sex is mainly decor and surface; she’s like a laminated piece of ersatz rococo furniture. Alarmingly, Generation Gaga can’t tell the difference. Is it the death of sex? Perhaps the symbolic status that sex had for a century has gone kaput; that blazing trajectory is over.

The web has been a communication revolution, the magnificent fulfilment of Marshall McLuhan’s prophecy of a “global village.” But it has also fragmnted and dispersed personal expression, draining energy from the performing arts, with their dynamic physicality. For a decade and a half, stars have steadily waned in power and sexual charge. Thus Gaga seems comet-like, a stimulating burst of novelty, even though she is a ruthless recycler of other people’s work. She is the diva of déjà vu. Gaga has glibly appropriated from performers like Cher, Jane Fonda as Barbarella, Gwen Stefani and Pink, as well as from fashion muses like Isabella Blow and Daphne Guinness. Drag queens, whom Gaga professes to admire, are usually far sexier in many of her over-the-top outfits than she is.

Peeping dourly through all that tat is Gaga’s limited range of facial expressions - something she has tried to make a virtue of in her song Poker Face, which perfectly describes her frosty mug, except when she goes weepy-tremulous or flashes a goofy, rabbit grin. Her videos repeatedly thrust that blank, lugubrious face at the camera and us; it’s creepy and coercive. Marlene and Madonna gave the impression, true or false, of being pansexual. Gaga, for all her writhing and posturing, is asexual. Going off to the gym in broad daylight, as Gaga recently did, dressed in a black bustier, fishnet stockings and stiletto heels isn’t sexy - it’s sexually dysfunctional. And it’s criminally counterproductive, erasing the cultural associations from that transgressive garb and neutering it. The gym-going Madonna, to her credit, has always been brutally honest about publicity showing herself in ratty gear with no make-up.

Gaga has become increasingly frank about airing her sexual issues, revealing that she is “quite celibate” and that she avoids sex because she fears losing her creativity through her vagina - an odd place for it to drain by any standard. Despite her phobias, her lyrics can be blatantly explicit, as in the crass clunker of a line “I wanna take a ride on your disco stick” (from Love Game). There’s more carpentry talk of a “vertical stick” in Bad Romance, where the theme is anal (”rear window”) and safely vagina-free. Gaga’s sexual reticence can’t be chalked up to priest-ridden guilt: although she was nominally raised Catholic, her father (an Internet entrepreneur who was once a bar-band rock musician in New Jersey) was clearly less repressive than Madonna’s old-school authoritarian Italian-Amercian father. In fact, the puritanical strictness of Madonna’s background sparked her ambition and strengthened her best work. Without taboos, there can be no transgression - which is why Madonna’s ideas waned after she drifted into misty Kabbalah.

There is no religious frame of reference in Gaga’s songs, aside from the passing assertion, “Got no salvation, got no religion” (in So Happy I Could Die); there is nothing remotely comparable to the sweeping gospel-choir crescendo of Madonna’s Like A Prayer. So it is unsurprising to hear that Gaga is consulting celebrity “spiritual guides” like Deepak Chopra.

Compare Gaga’s insipid songs, with their nursery-rhyme nonsense syllables, to the title and hypnotic refrain of the first Madonna song and video to bring her attention on MTV, Burning Up, with its elemental fire imagery and its then shocking offer of fellatio. In place of Madonna’s valiant life force, what we find in Gaga is a disturbing trend towards mutilation and death. Thus we get Gaga lyrics like “Show me your teeth”; “Need a man now, so show me your fangs”; “Take a bite of my bad girl meat” (from Teeth) - faintly sadistic cunnilingual jokes that must be the cat’s meow among smirky teens.