As doctors rush to prescribe viagra, few realize that nature already provides safe, natural ways to boost sexual desire, pleasure and fulfillment. Women Did You Know: Anise imitates the female hormone estrogen, increasing sexual intensity and satisfaction; Fenugreek, once fed to women in harems to augment breast size, is now used to elevate sex drive; The Chinese herb epimedium has a testosterone-like substance known to enhance a woman's sexual desire; The Mexican plant damiana is a sexual rejuvenator, aiding vitality by providing oxygen to the genital area.  Men Did You Know: Fennel moderates orgasm, allowing men to enjoy sex for a longer period of time; Brazilians have long drunk tea made from guarana seeds for the herb's aphrodisiac effect; 30 million American men suffer from impotence and over 200 prescription medications cause erectile dysfunction; South American quebracho and African yohimbe derivatives are used in prescription drugs to treat male impotence.