title: Parental separation, parental alcoholism, and timing of first sexual intercourse.
abstract: OBJECTIVE
  We examined timing of first voluntary sexual intercourse as a joint function of parental separation during childhood and parental history of alcoholism.
  
  
  METHODS
  Data were drawn from a birth cohort of female like-sex twins (n = 569 African ancestry [AA]; n = 3,415 European or other ancestry [EA]). Cox proportional hazards regression was conducted predicting age at first sex from dummy variables coding for parental separation and parental alcoholism. Propensity score analysis was also employed to compare intact and separated families, stratified by predicted probability of separation.
  
  
  RESULTS
  Earlier sex was reported by EA twins from separated and alcoholic families, compared to EA twins from intact nonalcoholic families, with effects most pronounced through the age of 14 years. Among AA twins, effects of parental separation and parental alcoholism were largely nonsignificant. Results of propensity score analyses confirmed unique risks from parental separation in EA families, where consistent effects of parental separation were observed across predicted probability of separation. For AA families, there was poor matching on risk factors presumed to predate separation, which limited interpretability of survival-analytic findings.
  
  
  CONCLUSIONS
  In European American families, parental separation during childhood is an important predictor of early-onset sex, beyond parental alcoholism and other correlated risk factors. To characterize risk for African Americans associated with parental separation, additional research is needed where matching on confounders can be achieved.
authors.affiliation: Department of Counseling and Educational Psychology, School of Education, Bloomington, Indiana University, Indiana; Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri. Electronic address: mwaldron@indiana.edu.
authors.forename: Mary
authors.initials: M
authors.lastname: Waldron
authors.affiliation: Department of Counseling and Educational Psychology, School of Education, Bloomington, Indiana University, Indiana.
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Doran
authors.affiliation: Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Kathleen K
authors.initials: KK
authors.lastname: Bucholz
authors.affiliation: Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; George Warren Brown School of Social Work, Washington University, St. Louis, Missouri.
authors.forename: Alexis E
authors.initials: AE
authors.lastname: Duncan
authors.affiliation: Addictions Department, Institute of Psychiatry, King's College, London, United Kingdom.
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lynskey
authors.affiliation: Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Pamela A F
authors.initials: PA
authors.lastname: Madden
authors.affiliation: Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut.
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Sartor
authors.affiliation: Midwest Alcoholism Research Center, Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Heath
mesh_terms: D000293:Adolescent; D000294:Adolescent Behavior / Q000523:psychology*; D000328:Adult; D000367:Age Factors; D000437:Alcoholism / Q000453:epidemiology*; D044383:Black People / Q000706:statistics & numerical data; D003075:Coitus / Q000523:psychology*; D004243:Divorce / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D008297:Male; D010290:Parents; D011247:Pregnancy; D012307:Risk Factors; D014427:Twins / Q000523:psychology*; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult; D001741:Black or African American
keywords: Parental alcoholism; Parental separation or divorce; Propensity score analysis; Sexual intercourse; Survival analysis