A minimal volume of 2ml
20 – 200 million spermatozoa per ml of semen. Less than 20 million sperms/ ml is called oligospermia while absence of sperms is called azoospermia. At least 40 million sperms must be present per ejaculate. Oligospermic males have a difficulty in conceiving and are at the risk of infertility as are azoospermic males.
75% of the spermatozoa must be living
Morphology of atleast 30% sperms must be normal
Rapidly progressing forward movement must be present in atleast 25% of sperms. Atleast 50 % of the spermatozoa must be motile even if sluggish.

Some tips to increase the sperm counts are as follows:

Diet: Diet plays an important role in improving fertility in males. The food consumed must contain essential amino acids, antioxidants like Vitamin C, D and E, trace elements like zinc , selenium etc. Consumption of fresh green leafy vegetables, fresh fruits, cereals , eggs , yoghurt, sea foods like oysters and lean meats offer a healthy diet which will not only improve the sperm counts but also the over function of the sperms.
Take supplements: Zinc is an important trace element which is known to improve sperm counts and can be supplemented in subjects who are deficient or in those who have reduces counts.
Exercise: Exercise to keep yourself fit and to avoid obesity. A five day, 40 minute exercise schedules are good enough to improve male fertility. Avoid cycling for a long time. This is likely to increase the testicular temperature which reduces spermatogenesis.
Avoid tight underpants: The natural position of the testes is away from the body so that its temperature is lower than that of the body which is essential for spermatogenesis. Wearing tight undergarments increases the temperature of the testes thereby decreasing sperm counts.
Avoid smoking: Various studies have proved smoking to have deleterious effects on sperm counts and sperm function.
Use Herbs: Pycnogenol is a herbal extract from the plant Maritime pine. It contains bioflavanoids and organic acids which are strong antioxidants. Korean ginseng is also a potent stimulator of testosterone secretion which directly increases spermatogenesis.
Electronic gadgets: The recent increase in the usage of electronic gadgets like laptops, mobile phones has also lead to decreasing sperms counts in men. It is best to avoid keeping laptops on the lap for a long time and also avoid keeping phones near the inguinal region. The electromagnetic radiations increase the temperature of the testes and reduce spermatogenesis.
Treatment of surgical causes: Conditions like varicocoeles and undescended testes can be surgically treated and monitored to see increasing counts post surgery. Incases where there is a blockage of the ducts leading to azoospermia, a vaso- epididymal anastamoses can bypass the block and open up the tubes and improve the sperm counts in the semen.
Treatment of medical causes: Immunological disorders like presence of antisperm antibodies also contribute to lowered sperm counts. Such conditions must be treated with steroids to suppress the autoimmune response and improve the counts.