male infertility male infertility male infertility refers to a sexually mature male's inability to impregnate a fertile female. in humans it accounts for 40–50% of infertility. it affects approximately 7% of all men. male infertility is commonly due to deficiencies in the semen, and semen quality is used as a surrogate measure of male fecundity. more recently, advance sperm analyses that examine intracellular sperm components are being developed. male infertilityspecialtyurology age considerations there is a decrease in sperm concentration as men age: 90% of seminiferous tubules in men in their 20s and 30s contain spermatids, whereas men in their 40s and 50s have spermatids in 50% of their seminiferous tubules, and only 10% of seminiferous tubules from men aged > 80 years contain spermatids. in a random international sample of 11,548 men confirmed to be biological fathers by dna paternity testing, the oldest father was found to be 66 years old at the birth of his child; the ratio of dna-confirmed versus dna-rejected paternity tests around that age is in agreement with the notion of general male infertility above age 65–66. causes factors relating to male infertility include: immune infertility antisperm antibodies (asa) have been considered as infertility cause in around 10–30% of infertile couples. asa production are directed against surface antigens on sperm, which can interfere with sperm motility and transport through the female reproductive tract, inhibiting capacitation and acrosome reaction, impaired fertilization, influence on the implantation process, and impaired growth and development of the embryo. risk factors for the formation of antisperm antibodies in men include the breakdown of the blood‑testis barrier, trauma and surgery, orchitis, varicocele, infections, prostatitis, testicular cancer, failure of immunosuppression and unprotected receptive anal or oral sex with men. genetics chromosomal anomalies and genetic mutations account for nearly 10–15% of all male infertility cases. klinefelter syndrome one of the most commonly known causes of infertility is klinefelter syndrome, which affects one in 500–1000 newborn males. klinefelter syndrome is a chromosomal defect that occurs during gamete formation due to a non-disjunction error during cell division. resulting in males having smaller testes, reducing the amount of testosterone and sperm production. males with this syndrome carry an extra x chromosome (xxy), meaning they have 47 chromosomes compared to the normal 46 in each cell. this extra chromosome directly affects sexual development before birth and during puberty. a variation of klinefelter syndrome is when some cells in an individual have the extra x chromosome but others do not, referred to as mosaic klinefelter syndrome. the reduction of testosterone in the male body normally results in an overall decrease in the production of viable sperm for these individuals thereby forcing them to turn to fertility treatments to father children. y chromosome deletions y chromosomal infertility is a direct cause of male infertility due to its effects on sperm production, occurring in approximately one in 2000 males. usually, affected men show no symptoms, although they may have smaller testes. men with this condition may exhibit azoospermia (no sperm production), oligozoospermia (small number of sperm production), or they may produce abnormally shaped sperm (teratozoospermia). this case of infertility occurs during the development of gametes in the male. where a normal healthy male will have both an x and a y chromosome, affected males have genetic deletions in the y chromosome. these deletions affect protein production that is vital for spermatogenesis. studies have shown that this is an inherited trait; if a male is fathered by a man who also exhibited y chromosome deletions then this trait will be passed down. these individuals are thereby "y-linked". daughters are not affected and cannot be carriers due to their lack of a y chromosome. other age group 12–49 (paternal age effect) aneuploidy, an abnormal number of chromosomes centriole neoplasm, e.g. seminoma idiopathic failure cryptorchidism trauma hydrocele, particularly hydrocele testis hypopituitarism in adults, and hypopituitarism untreated in children (resulting in growth hormone deficiency and proportionate dwarfism.) mumps malaria testicular cancer defects in usp26 in some cases acrosomal defects affecting egg penetration idiopathic oligospermia – unexplained sperm deficiencies account for 30% of male infertility. pre-testicular causes pre-testicular factors refer to conditions that impede adequate support of the testes and include situations of poor hormonal support and poor general health including: varicocele varicocele is a condition of swollen testicle veins. it is present in 15% of normal men and in about 40% of infertile men. it is present in up to 35% of cases of primary infertility and 69–81% of secondary infertility. hypogonadotropic hypogonadism due to various causes obesity increases the risk of hypogonadotropic hypogonadism. animal models indicate that obesity causes leptin insensitivity in the hypothalamus, leading to decreased kiss1 expression, which, in turn, alters the release of gonadotropin-releasing hormone (gnrh). undiagnosed and untreated coeliac disease (cd). coeliac men may have reversible infertility. nevertheless, cd can present with several non-gastrointestinal symptoms that can involve nearly any organ system, even in the absence of gastrointestinal symptoms. thus, the diagnosis may be missed, leading to a risk of long-term complications. in men, cd can reduce semen quality and cause immature secondary sex characteristics, hypogonadism and hyperprolactinaemia, which causes impotence and loss of libido. the giving of gluten free diet and correction of deficient dietary elements can lead to a return of fertility. it is likely that an effective evaluation for infertility would best include assessment for underlying celiac disease, both in men and women. drugs, alcohol strenuous riding (bicycle riding, horseback riding) medications, including those that affect spermatogenesis such as chemotherapy, fluoxetine, anabolic steroids, cimetidine, spironolactone; those that decrease fsh levels such as phenytoin; those that decrease sperm motility such as sulfasalazine and nitrofurantoin genetic abnormalities such as a robertsonian translocation tobacco smoking