Endocrine Abstracts

From an evolutionary point of view, reproduction is one of the key events. Thus, any potential threat to human fertility, needs to be taken seriously by researchers as well as the general public. In 1992 a meta-analysis of 63 published papers, indicated almost 50% reduction of sperm counts during the period 1940 to 1990. Since then, the discussion on whether the sperm numbers are decreasing or not has divided the scientific world into believers and non-believers. A concomitant rise in the incidence of testicular cancer and, possibly, even congenital malformations of male genitalia, has been claimed as support to the hypothesis of negative secular trend in male reproductive function. The rapidity by which these changes have occurred has pointed to non-genetic causes – life style changes and/or environmental exposure to so called endocrine disrupters (ED). Whereas animal studies have shown that ED given in sufficiently high doses, may possess a negative effect on male reproduction we are still looking for a “smoking gun” in the context of human exposure. So far, relatively weak associations between exposure to ED – at doses normally found in humans – and semen parameters, have been reported. However, it has been hypothesized that male reproductive organs are mostly vulnerable to the negative effect of ED, during early fetal period. Human studies, linking fetal exposure to male reproductive function are still very scarce and, therefore, not yet conclusive. During the next few years we can expect more robust data based on utilization of several biobanks of maternal blood obtained during early pregnancy. However, recent research has indicated the impaired male fertility may be associated with increased risk of long-term comorbidity including metabolic and cardiovascular diseases, osteoporosis as well as cancer. With up to 40% of men having – from fertility point of view – suboptimal sperm counts, the threat to the human race may not only be related to suboptimal fertility rates but also to reduced life expectance and unhealthy aging.