About 30 percent of all five-year-olds—up from 10 percent a decade ago—do not know which hand to hold a pencil in because they are unsure whether they are right- or left-handed, reports The Daily Telegraph.

Some children who cannot write or draw are being incorrectly diagnosed with development problems, when they may simply be having difficulty because they haven’t yet established a dominant hand, reports The Daily Mail.

Child development experts say that the news is more evidence that today’s children are suffering from delayed development, and expressed concern that they could suffer adverse effects into adulthood. In previous research, educational psychologist Madeleine Portwood found that 57 percent of three-year-olds are not able to carry out age-appropriate tasks.

Overcautious parents are unwittingly contributing to the problem, Portwood says. Many parents are no longer allowing their infants to lie or crawl on their fronts out of fear of Sudden Infant Death Syndrome (SIDS), and it is hampering development of dexterity and left-right coordination.