generally has a life expectancy which is considered to depend on ph, temperature, presence of air and other factors, and is unpredictable but smaller than the life expectancy inside the human body. for instance, sperm donors who collect the sample outside the clinic are advised to have handed in the sample no more than one hour from collection, and to keep it, if not at body temperature, then at least at room temperature. in a non-harmful environment outside the body, such as in a sterile glass container the number of motile sperm decreases by approximately 5–10% per hour. in contrast, in a latex condom, the quality decreases by 60–80% per hour, rendering the sample unusable in a relatively short time. in female the environment in the uterus and fallopian tubes are advantageous. a pregnancy resulting from sperm life of eight days has been documented. others tobacco smoking lowers the sperm quality, perhaps by decreased ability to attach to hyaluronan on the egg cell. wright et al. have reviewed evidence that smoking is associated with increased sperm dna damage and male infertility. smoking cannabis can decrease sperm quantity. long-term stress is also suggested. the practise of tucking can reduce both the sperm count and sperm quality. meta-analysis indicates that mobile phone exposure affects sperm quality negatively. higher levels of intelligence are also correlated with higher levels of sperm quality in three key indicators: sperm concentration, sperm count and sperm motility. men who scored high on a battery of intelligence tests tended to have higher counts of healthy sperm, while low scorers tended to have fewer and more sickly sperm. it is conceivable that intelligence might tip off a man's overall health to women looking for a mate with healthy genes, explained university of new mexico evolutionary psychologist geoffrey miller at a talk at harvard university. "though the connections between brains and sperm were 'not awesome, they're there and highly significant,' miller said. all things held equal, good sperm and good brains go together." regarding diet, malnutrition or an unhealthy diet can lead to e.g. zinc deficiency, lowering sperm quality. sperm quality is better in the afternoon than in the morning. adrenaline-levels are higher during awakening (~06.00 to noon), which may contribute similarly to general stress. lack of exercise, as well as excessive exercise, are minor factors. in professional sports, semen quality parameters tend to decrease as training requirements increase. the effect differs substantially between different professional sport types. for example, water polo appears substantially less harmful to semen quality than triathlon. a longer duration of sexual stimulation before ejaculation slightly increases sperm quality. males carrying robertsonian translocations in their chromosomes have significantly higher degree of sperm cell apoptosis and lower concentration. sperm cells also have decreased forward motility, but normal morphology. testicular cancer, leydig cell tumours and sertoli cell tumours are also associated with reduced sperm count and quality. tests semen analysis main article: semen analysis a semen analysis typically measures the number of sperm per millilitre of ejaculate, and analyzes the morphology (shape) and motility (ability to swim forward) of the sperm (the typical ejaculate of a healthy, physically mature young adult male of reproductive age with no fertility-related problems usually contains 300–500 million spermatozoa, though only a couple of hundred survive in the acidic environment of the vagina to be candidates for successful fertilization). also usually measured are the concentration of white blood cells, the level of fructose in the semen, and the volume, ph, and liquefaction time of the ejaculate. hamster zona-free ovum test main article: hamster zona-free ovum test a man's sperm are mixed with hamster eggs that have had the zona pellucida (outer membranes) removed, and the number of sperm penetrations per egg is measured. no strong correlation has been found between hamster egg penetration rates and the various semen parameters and the role of the hamster egg penetration test in the investigation of the causes of infertility should be evaluated further. however, a negative result on the hamster test correlates with a lower probability of the man's partner becoming pregnant. antisperm antibodies test presence of antisperm antibodies may be responsible for sperm agglutination, reduced sperm motility, abnormal postcoital test. several tests are presently available including sperm immobilization test, sperm agglutination tests, indirect immunofluorescence test, enzyme-linked immunosorbent assay, radiolabelled antiglobulin assay. one of the most informative and specific tests is immunobead rosette test which can identify different antibody classes involved (igg, iga, igm) and location on the sperm cell (head, body or tail). hemizona test hemizona test is a test to evaluate sperm zona-binding capacity. in this test, the two halves of human zona pellucida is incubated with patient's capacitated sperm and control fertile donor's sperm. other tests pcr-based detection of the pathogens in the semen of patients with asymptomatic genital infection. biochemical markers like creatine kinase, reactive oxygen species. cryopreservation when performing cryopreservation of semen, it is the sperm quality after reviving the sample that is of importance, because many sperm cells die in the process. to be of use in assisted reproductive technology, the sample should after thawing have more than 5 million motile sperm cells per ml with a good grade of mobility. if the grade of mobility is poor, 10 million motile cells per ml is required. home insemination of previously frozen sperm can be accomplished with the use of a cervical cap conception device as a delivery system for the sperm. bad freezers in 10–20% of all men, the semen does not endure cryopreservation. the cause is unknown. it does not necessarily mean an otherwise bad semen quality. sperm washing when a sperm sample is prepared for intrauterine insemination, it is washed at a facility such as a fertility clinic or a sperm bank. some sperm does not survive the washing process, as is also the case when freezing the sperm.