1166 (Guilamo-Ramos et al. 2006). Other factors that can limit parents’ sexual communication with their children have also been reported, including lack of an opportune time, lack of conﬁdence, a child being too young, and the per- ception that the child is unreceptive (Jaccard et al. 2002; Miller et al. 2007; Wilson et al. 2010). Research Questions and Hypotheses Research on sexual communication between parents and their children dates back about three decades. But as Lefkowitz (2002) noted, it can be difﬁcult to obtain willing samples due to the sensitive nature of this topic, and rep- resentative samples are needed to assure that researchers are capturing perspectives, behaviors, and associations that reﬂect those of the populations of interest. Adding to a literature with few representative-sample studies on par- ent–child sexual communication, we report on the present study that employed a representative statewide sample of households with children aged 8–18 years from a large and diverse state in the United States to investigate aspects of parent’s communication about sex with their preadolescent and adolescent children. In the remainder of this article, we use the terms adolescent and adolescents to refer to the pre, early, middle, and late adolescents who were the focus of the questions asked of their parents. First, we examined the extent to which parents report communicating with their adolescents about sex and sex- uality, together with their perceived levels of comfort and knowledge in this sexual communication. In addition, we explored the extent to which parents report difﬁculties in communicating with their adolescents about sex and sex- uality and the types of difﬁculties they report. Finally, we examined the predictability of sexual communication by demographic characteristics of parents and adolescents, as well as the additional predictive power of parents’ per- ceived levels of comfort, knowledge, and difﬁculties experienced. On the basis of the prior research discussed above, we hypothesized that adolescent and parent age, adolescent and parent gender, parent Hispanic ethnicity, parent edu- cation, and parent religious attendance in a typical month would predict extent of sexual communication, that ado- lescent gender would moderate the effect of parent gender, and that self-reported levels of comfort, knowledge, and difﬁculties experienced would add additional predictive power when demographic factors are controlled. More speciﬁcally, we expected that the number of topics dis- cussed would be greater for parents of older adolescents. We also expected that mothers would report a greater number of topics discussed than would fathers, and that mothers would be more likely to talk with daughters than 123 J Youth Adolescence (2010) 39:1164–1174 would fathers, and that fathers would be more likely to talk with sons than would mothers. We also predicted that Hispanic parents, parents with lower educational levels, and parents with more frequent religious attendance would discuss fewer topics. Finally, we expected that parents who report lower levels of comfort and knowledge and parents who report a sexual communication difﬁculty would talk about fewer topics. Method This study employed a subset of data from a list-assisted, random-digit-dial statewide survey we conducted on parental beliefs, preferences, and practices regarding sexuality education and adolescent sexual health services in California (Constantine et al. 2007). The Public Health Institute’s institutional review board reviewed the survey instrument and protocol and declared them exempt. Data collection took place in the spring and summer of 2006. Sampling The sampling frame was based on the population of all households with a telephone in California. The person answering the phone was asked the number of adults and the number of children aged 18 years and younger in the household, and to identify a parent in the household. If a parent was available, he or she was read the informed consent script and then invited to participate. Follow-up appointments were made if the parent was unable to complete the interview at that time. Initial calls were conducted in English, and Spanish-speaking interviewers called back respondents who spoke Spanish. At least ten calls were made to consistently unanswered or busy phone numbers and answering machines. The total sample consisted of 1,284 parents who com- pleted interviews. A response rate of 53% was calculated using the RR3 method of the American Association for Public Opinion Research (2006). This method divides the number of completed interviews by the estimated number of eligible households called, which is estimated by a formula involving known eligible and ineligible house- holds, and those of unknown eligibility. The total sample was based on subsampling within California’s ﬁve all- inclusive regions consisting of groups of counties orga- nized by geographic and demographic similarity. To compensate for the difference in selection probabilities resulting from higher sampling rates in smaller regions, we used stratum weights in this study’s statewide analyses. The resulting design effect attributable to weighting was minimal (1.13).