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Influence of GSTT1 null genotype on the offspring sex ratio of gasoline filling station workers
  1. M Ansari-Lari1,
  2. M Saadat2,
  3. N Hadi1
  1. 1Department of Community Medicine, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
  2. 2Department of Biology, College of Sciences, Shiraz University, Shiraz, Iran
  1. Correspondence to:
 Dr M Saadat
 Department of Biology, College of Sciences, Shiraz University, Shiraz 71454, Iran;


The aim of this study was to investigate whether the occupational exposure to gasoline of men employed at filling stations affects the sex of their children. Altogether 115 offspring (47 males, 68 females) were identified within families of 49 men working in filling stations in Shiraz (Fars province, south of Iran) and 345 offspring (178 males, 167 females) from 147 families of unexposed persons from the general population of Shiraz, which were matched by age of fathers (±2 years) and number of children as a control group. The offspring sex ratio at birth (male proportion) in the filling station workers was significantly lower than the ratio in control group (OR = 0.65; 95% confidence intervals (CI) 0.42 to 0.99). Genotypes of glutathione S-transferase M1 (GSTM1) and T1 (GSTT1) were investigated on extracted genomic DNA of 37 exposed workers using the polymerase chain reaction based method. In exposed group with active GSTM1 and GSTT1 genes, offspring sex ratio was the same as the ratio in the control group (OR = 0.66; 95% CI 0.34 to 1.28). However, in the exposed group with active GSTM1 and null genotype of GSTT1, the offspring sex ratio statistically decreased (OR = 0.45; 95% CI = 0.21 to 0.96). It seems that the GSTT1 null genotype has an effect on offspring sex ratio in the filling station workers.

  • glutathione S-transferase
  • sex ratio
  • gasoline
  • occupational exposure
  • PCR, polymerase chain reaction
  • GST, glutathione S-transferase

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  • Funding: this study was supported by Shiraz University.

  • Conflicts of interest: none declared.

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