Figure 1.

Decrease in mean morphology values over 39 years (1969–2008). The population consists of hospital patients with complaints of infertility who donated semen samples for evaluation at the Andrology Laboratory, Department of Obstetrics and Gynecology, Tygerberg Academic Hospital, South Africa. Since the beginning of 1971, sperm morphology evaluation and control have been performed by one person (RM). No conscious or deliberate changes in the evaluation criteria have been introduced since the mid-1970s, at which time strict evaluation criteria were introduced. Modified from Menkveld et al. ⁴².