Stretch marks are the result of dramatic tension to the skin which causes a rupturing of skin fibers. Stretch marks can develop at any age. Not everyone gets them, and genetics play a role. Stretch marks usually appear when people have a growth spurt during puberty, pregnancy, rapid weight loss or gain, or rapid muscle growth from weight training. They’re more common in women than in men, and they can show up on almost any area of the body. Typically, young stretch marks look pale pink or red, depending on your skin tone. These raised scars can feel itchy. As stretch marks mature, they usually become paler.