Twenty-three years of sexual rejection might have been too much. The San Francisco Zoo's new male gorilla, successor to the late and virile Kubi, is finally spending quality time with the public and his four female companions -- and so far, the public seems more interesting. 'Sometimes the libido doesn't kick in right away,' said longtime gorilla keeper Mary Kerr. Zoo spokeswoman Nancy Chan put it more bluntly. 'He's a wimp,' she said. ... [O]ne thing is clear: he's still a virgin at 23, spurned repeatedly by the four females in Buffalo, who preferred a short, dumpy ape called Omega. 'You can sort of tell he's inexperienced,' Kerr said. 'He's not as assertive as most silverbacks would be.' ... 'He's too nice a guy,' Chan said. 'It might be the problem with why he never bred.'