INTRODUCTION

It is estimated that male subfertility is present in up to 40–50 percent of infertile couples, alone or in combination with female factors (1).

The correct approach for male infertility evaluation should include a rational program composed of the careful evaluation of the patient's history, a complete physical examination, laboratory tests of basic/extended semen analysis, and an urological, endocrinological, and genetic workup, as appropriate (2).

Several semen parameters are used to discriminate the fertile male from the subfertile male. The most widely used parameters are sperm concentration, motility, progressive motility, and sperm morphology. All of these parameters are important and must not be used alone to make clinical decisions or seen in isolation. Sperm morphology is, however, the single sperm indicator most widely debated in the literature. A large number of classification systems have been used to describe which cellular features constitute a morphologically normal/abnormal spermatozoon. The most widely accepted classification systems for sperm morphology are the World Health Organization (WHO) criteria of 1987 and 1992 (3, 4) and the Tygerberg strict criteria, now also used by the WHO since 1999 (5–5).

Although there is a positive correlation between normal semen parameters and male fertility potential, the threshold values for fertility/subfertility according to WHO criteria 1987 and 1992 (3, 4) are of little clinical value in discriminating between the fertile and subfertile male (9–13).