Molybdenum Exposure and Semen Quality: Meeker et al. Respond

We appreciate the comments by Sorahan and Sullivan that serve to reiterate the limitations we discussed in our article reporting relationships between metal concentrations in blood and semen quality among 219 men recruited through two Michigan infertility clinics (Meeker et al. 2008). As highlighted in their letter, these limitations included the possibility of chance findings due to multiple comparisons and the sensitivity of the molybdenum assay used, among others. However, dismissing our analysis as a “fishing expedition” is not appropriate, given the animal evidence for adverse effects on male reproductive function in relation to Mo (Institute of Medicine 2001; Jeter and Davis 1954; Lyubimov et al. 2004; Pandey and Singh 2002; Thomas and Moss 1951; Van Niekerk and Van Niekerk 1989; Vyskocil and Viau 1999; Yamaguchi et al. 2007) and other metals. Because evidence exists for numerous metals to be either harmful or beneficial to male reproduction, and because metals may interact with one another synergistically or antagonistically, we conducted this exploratory study to provide the most comprehensive human data to date on multiple metals and semen quality.