DUNEDIN, New Zealand, Feb. 6 (UPI) -- Heavy use of marijuana -- 40 times a year -- has been shown to contribute to gum disease in younger adults, a study in New Zealand found.

DURHAM, N.C., Nov. 6 (UPI) -- Breastfeeding raised intelligence an average of nearly 7 IQ points in children, who had the gene FADS2, U.S. and British researchers found.

WASHINGTON, July 18 (UPI) -- Scientists have found variations of the same gene can determine whether people develop depression after a traumatic event or escape unscathed.

WASHINGTON, Aug. 8 (UPI) -- The UPI think tank wrap-up is a daily digest covering brief opinion pieces, reactions to recent news events and position statements released by various think tanks. This is the second of two wrap-ups for Aug. 8.