(CBAVD), which may be associated with abnormalities or agenesis of the epididymis, seminal vesicles or kidneys, and indicate the need for testicular sperm extraction. TRUS plays a key role in assessing azoospermia caused by obstruction, and detecting distal CBAVD or anomalies related to obstruction of the ejaculatory duct, such as abnormalities within the duct itself, a median cyst of the prostate (indicating a need for cyst aspiration), or an impairment of the seminal vesicles to become enlarged or emptied. Hyposmotic test To check if the plasma membrane of the sperm is working properly or if it is damaged. To do this, the spermatozoa are placed in a hypotonic medium (low in salts), which causes an osmotic imbalance in the cells, causing the medium to enter the interior of the spermatozoon and swell it. If the sperm membrane is damaged, it will not be functional, so fertilization cannot take place. Hence the relevance of this test. Sperm FISH To check if the spermatozoa have a normal set of chromosomes. It provides great information about the seminal quality of the male. It is performed by marking specific chromosomes of the sperm with fluorescent DNA probes. Some situations in which sperm FISH is indicated are the following: -Alterations in the karyotype. -Altered seminogram, especially in cases with low concentration or serious morphology problems. -Man undergoing chemotherapy or radiotherapy. -Couples with recurrent miscarriages of unknown cause. -Implantation failure on repeated occasions after applying assisted reproductive techniques. -Couples who have had a child with some chromosomal alteration. Advanced age. Prevention Some strategies suggested or proposed for avoiding male infertility include the following: Avoiding smoking as it damages sperm DNA Avoiding heavy marijuana and alcohol use. Avoiding excessive heat to the testes. Maintaining optimal frequency of coital activity: sperm counts can be depressed by daily coital activity and sperm motility may be depressed by coital activity that takes place too infrequently (abstinence 10–14 days or more). Wearing a protective cup and jockstrap to protect the testicles, in any sport such as baseball, football, cricket, lacrosse, hockey, softball, paintball, rodeo, motorcross, wrestling, soccer, karate or other martial arts or any sport where a ball, foot, arm, knee or bat can come into contact with the groin. Diet: Healthy diets (i.e. the Mediterranean diet) rich in such nutrients as omega-3 fatty acids, some antioxidants and vitamins, and low in saturated fatty acids (SFAs) and trans-fatty acids (TFAs) are