Although many mothers prefer to leave their children with a family member rather than a formal daycare center, new research published in the Journal of Labor Economics shows that this may not be good for kids IQ test scores.

Researchers from various international universities studied children who stay with their mothers during the day as well as those who go to a preschool or a licensed daycare center. These kids were then compared with those who had informal care, such as that from a friend or family member.

Results from the study indicated that children between the ages of 2 and 6 who have informal care are more prone to having delayed cognitive development. On average, each year of this type of care can reduce a child's standardized test scores by almost 3 percent compared with children who stay with their mothers.

The team of researchers believe that the results show that children who are separated from their mothers can suffer negative effects, which can be diminished if the child is in a suitable daycare program. Additionally, this is another indication that children's early experiences can help mold their academic achievements later in life.