A recent study funded by the NSF found that how much time new parents spend talking about numbers affects how well their children learn basic math later in life. Researchers listened to recordings of caregivers interacting with their children during everyday tasks and noted the incidences of number-related talk; some parents mentioned as few as four number words during the study, while others mentioned number words over 250 times. Children whose parents mentioned number words more often were more likely to understand the "cardinal number principle," which says that "the size of a set of objects is determined by the last number reached when counting the set (e.g., a set of 10 items is larger than a set of seven items)."
Research into early childhood development in the past few decades has increasingly shown that very young children are constantly absorbing new information around them and that even the smallest interaction with adults or other children can be loaded with meaning. I can't help but wonder if the principle discovered in this study also applies to science--if parents who talk more about science affect their children's interest in science later in life. And most kids like to build structures with blocks and do puzzles--both of which use engineering concepts. Perhaps one way to increase interest in STEM subjects is to make them a part of the lives of young children.