Between the ages of 6 and 12, the first outward signs of puberty often occur, and both boys and girls become more private about their bodies. Children begin building a larger knowledge base about sexual information—and acquire information from many sources, including their parents/caregivers, peers, and siblings. During the middle childhood to preteen years, children often play in same-sex groups and may begin masturbating, engaging in sexual fantasy, and/or sexual contact.