Pregnant women are being told that using perfume or scented creams increases the risk of their children suffering infertility later in life, the BBC reports. Researchers at the University of Edinburgh say that the 8 to 12 week gestation period is a critical window for determining future reproductive problems. They believe that if the fetus is exposed to chemicals from cosmetics during this period, it can affect the child’s sperm production later on. However, they stressed that this is only a preliminary finding and the researchers have not yet reached a final conclusion. The study was led by Richard Sharp, a professor at the Medical Research Council’s Institute of Human Reproductive Sciences in Edinburgh. In the study conducted on rats, they blocked androgens, including testosterone. The experiments confirmed that if these hormones were blocked, the rats became infertile. Some of the chemicals used to block androgens are widely used in the production of items such as cosmetics, household fabrics and plastics.