Twice-vasectomized chimps having accident babies

In humans and chimps, a vasectomy involves severing the vas deferens, the narrow tube that carries sperm from the testicles to the urethra. The original procedure involved snipping a one- to two-inch section from the vas deferens and cauterizing the ends. But in some cases, those ends have proven able to regrow and reattach within five years. Of the 13 males examined at Chimp Haven, 12 of the vasectomies had regrown. 

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