Keeping current on adult vaccines could be important to your child's health. New research from the University of North Carolina at Chapel Hill shows that more than 75 percent of babies with whooping cough  -- a.k.a. pertussis, which can be deadly in infants  -- contracted the infection from someone in their household, usually a parent. Many adults don't realize that their own childhood pertussis vaccine wears off over time. And infants don't receive theirs until the age of 2 months, leaving them vulnerable in the earliest weeks of life. Ask your doctor about a booster shot called Tdap (the vaccine your baby gets in four doses is called DTaP), which combines protection against pertussis with vaccines for tetanus and diphtheria, and may be administered in the second or third trimester of pregnancy.