title: Focus issue on male infertility.
abstract: Male infertility problems can occur when sperms are limited in number or function. In this paper, we describe the clinical evaluation of male infertility. A detailed history, physical examination, and basic semen analysis are required. In addition, ultrasound, karyotyping, and hormonal studies are needed to determine specific causes of infertility. In addition, the World Health Organization (WHO, 2009) has developed a manual to provide guidance in performing a comprehensive semen analysis. Among the possible reasons for male infertility, nonobstructive azoospermia is the least treatable, because few or no mature sperm may be produced. In many cases, men with nonobstructive azoospermia typically have small-volume testes and elevated FSH. Although treatment may not completely restore the quality of semen from men with subnormal fertility, in some cases a successful pregnancy can still be achieved through assisted reproductive technology.
authors.affiliation: Department of Urology, Toho University School of Medicine, Tokyo 143-8541, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Nagao
authors.forename: Koichi
authors.initials: K
authors.lastname: Nakajima