Shocking but true. Upon consumption caffeine passes through the placenta and enters every organ of a developing fetus. Furthermore, caffeine can also be transmitted to infants through breast milk. Because babies lack the enzymes necessary to breakdown caffeine, it can stay in their system for up to 85 hours!!!! Even in children, caffeine lingers around in the body for longer than it does in an adult. Hence, children should stay away from caffeine, and that includes soft drinks!
—I learned about this fact from: Gilbert RM. Caffeine, the most popular stimulant. The encyclopedia of psychoactive drugs. Chelsea House Publishers: New York, 1992.