MedGen

Absence of any measurable level of sperm,whereby spermatozoa cannot be observed even after centrifugation of the semen pellet. [from HPO]

Inability to conceive for at least one year after trying and having unprotected sex. Causes of female infertility include endometriosis, fallopian tubes obstruction, and polycystic ovary syndrome. Causes of male infertility include abnormal sperm production or function, blockage of the epididymis, blockage of the ejaculatory ducts, hypospadias, exposure to pesticides, and health related issues. [from NCI]

The inability of the male to effect fertilization of an ovum after a specified period of unprotected intercourse. Male sterility is permanent infertility. [from MONDO]

A mode of inheritance that is observed for traits related to a gene encoded on the mitochondrial genome. Because the mitochondrial genome is essentially always maternally inherited, a mitochondrial condition can only be transmitted by females, although the condition can affect both sexes. The proportion of mutant mitochondria can vary (heteroplasmy). [from HPO]

Absence of any measurable level of sperm in his semen, resulting from a defect in the production of spermatozoa in the testes. This can be differentiated from obstructive azoospermia on the basis of testicular biopsy. [from HPO]

Absence of any measurable level of sperm in his semen, resulting from post-testicular obstruction or retrograde ejaculation. This can be differentiated from obstructive azoospermia on the basis of testicular biopsy. [from HPO]

Any deviation from the normal concentration of threonine in the blood circulation. [from HPO]

An abnormal functionality of the genital system. [from HPO]

Any deviation from the normal concentration of serine in the blood circulation. [from HPO]

An anomaly of the testicle (the male gonad). [from HPO]

A rare, genetic male infertility due to a sperm disorder characterized by the absence of a measurable amount of spermatozoa in the ejaculate (azoospermia), or a number of sperm in the ejaculate inferior to 15 million/mL (oligozoospermia), resulting from a mutation in a single gene known to cause azoo- or oligo-spermia. Sperm morphology may be normal. [from ORDO]