Fathers who use cocaine at the time of conceiving a child may be putting their sons at risk of learning disabilities and memory loss. The findings of the animal study were published online in Molecular Psychiatry by a team of researchers from the Perelman School of Medicine at the University of Pennsylvania. The researchers say the findings reveal that drug abuse by fathers - separate from the well-established effects of cocaine use in mothers - may negatively impact cognitive development in their male offspring. An article in Medical News Today noted that the research showed that cocaine use in dads caused epigenetic changes in the brain of their sons, thereby changing the expression of genes important for memory formation. D-serine, a molecule essential for memory, was depleted in male rats whose father took cocaine and replenishing the levels of D-serine in the sons' hippocampus improved learning in these animals.