(1) woman reasons:
"1" ovulatory disorder: a variety of diseases result from abnormal regulation of the endocrine and the impact of ovarian dysfunction, leading to anovulation or ovulation;
"2" systemic factors: the spirit of psychology, nutrition, obesity, lack of a living system such as its effect on reproductive function;
"3" congenital genital abnormalities, such as gender abnormal sex, the hymen, vagina, uterus, fallopian tubes, ovaries, or absence of dysplasia or deformity, etc.;
"4" genital infections: such as vulvitis, vaginitis, cervicitis, endometritis, salpingitis, ovarian inflammation, pelvic inflammatory disease and genital tract tuberculosis, syphilis and other infectious diseases;
"5" Other genital lesions, such as vaginal scar, uterine fibroids, endometriosis, abnormal uterine position.

(2) man reasons:
"A" sperm abnormalities: such as azoospermia, oligospermia, sperm activity weak, morphological abnormalities, and poor semen liquefaction;
"2" genital lesions, systemic chronic wasting disease, smoking, alcohol-induced chronic poisoning, mental stress or psychological metamorphosis;
"3" impede the delivery of sperm; such as the vas deferens obstruction, impotence, premature ejaculation, no ejaculation, retrograde ejaculation so sperm can not be placed in the vagina, through the cervical mucus;
"4" immune factors: the body produces anti-sperm antibodies, sperm agglutination but not through the cervical mucus;
"5" Male hyperprolactinemia: Multi showed varying degrees of gonadal development and sexual dysfunction, impotence, lack of or no sexual desire.

Dong's Chinese Medicine Research Institute, Shijiazhuang Tel :0311-88468620