Parent-child sex communication results in the transmission of family expectations, societal values, and role modeling of sexual health risk-reduction strategies. Parent-child sex communication's potential to curb negative sexual health outcomes has sustained a multidisciplinary effort to better understand the process and its impact on the development of healthy sexual attitudes and behaviors among adolescents. This review advances what is known about the process of sex communication in the United States by reviewing studies published from 2003 to 2015. We used the Cumulative Index to Nursing and Allied Health Literature (CINAHL), PsycINFO, SocINDEX, and PubMed, and the key terms "parent child" AND "sex education" for the initial query; we included 116 original articles for analysis. Our review underscores long-established factors that prevent parents from effectively broaching and sustaining talks about sex with their children and has also identified emerging concerns unique to today's parenting landscape. Parental factors salient to sex communication are established long before individuals become parents and are acted upon by influences beyond the home. Child-focused communication factors likewise describe a maturing audience that is far from captive. The identification of both enduring and emerging factors that affect how sex communication occurs will inform subsequent work that will result in more positive sexual health outcomes for adolescents.