Variables in data file 1. id - identification number 2. pluralty - 5= single fetus 3. outcome - 1= live birth that survived at least 28 days 4. date - birth date where 1096=January1,1961 5. gestation - length of gestation in days 6. sex - infant's sex 1=male 2=female 9=unknown 7. wt - birth weight in ounces (999 unknown) 8. parity - total number of previous pregnancies including fetal deaths and still births, 99=unknown 9. race - mother's race 0-5=white 6=mex 7=black 8=asian 9=mixed 99=unknown 10 age - mother's age in years at termination of pregnancy, 99=unknown 11 ed - mother's education 0= less than 8th grade, 1 = 8th -12th grade - did not graduate, 2= HS graduate--no other schooling , 3= HS+trade, 4=HS+some college 5= College graduate, 6&7 Trade school HS unclear, 9=unknown 12 ht - mother's height in inches to the last completed inch 99=unknown 13 wt - mother prepregnancy wt in pounds, 999=unknown 14 drace - father's race, coding same as mother's race. 15 dage - father's age, coding same as mother's age. 16 ded - father's education, coding same as mother's education. 17 dht - father's height, coding same as for mother's height 18 dwt - father's weight coding same as for mother's weight 19 marital 1=married, 2= legally separated, 3= divorced, 4=widowed, 5=never married 20 inc - family yearly income in $2500 increments 0 = under 2500, 1=2500-4999, ..., 8= 12,500-14,999, 9=15000+, 98=unknown, 99=not asked 21. smoke - does mother smoke? 0=never, 1= smokes now, 2=until current pregnancy, 3=once did, not now, 9=unknown 22. time - If mother quit, how long ago? 0=never smoked, 1=still smokes, 2=during current preg, 3=within 1 yr, 4= 1 to 2 years ago, 5= 2 to 3 yr ago, 6= 3 to 4 yrs ago, 7=5 to 9yrs ago, 8=10+yrs ago, 9=quit and don't know, 98=unknown, 99=not asked 23. number - number of cigs smoked per day for past and current smokers 0=never, 1=1-4 2=5-9, 3=10-14, 4=15-19, 5=20-29, 6=30-39, 7=40-60, 8=60+, 9=smoke but don't know, 98=unknown, 99=not asked