Objective: To evaluate whether parents-adolescents relationship was associated with early sexual debut and having multiple partners in a low socioeconomic suburb in Mexico City. Methods: An anonymous questionnaire about sexual activity and relationships with parents during adolescence was responded by 936 participants, aged 20-30. Logistic regression was conducted. Results: The majority of participants reported being sexually active (78.3%). Among them, 70% of males and 55% of females had first sex before age 18. Good communication with parents during adolescence was inversely associated with sexual debut <18 (OR=0.40; CI95% 0.30-0.53) and having >2 sexual partners (OR=0.47; IC95% 0.33-0.68). Sexual debut <18 was associated with having had multiple partners (OR=3.86; IC95% 2.60-5.73). Conclusion: Good parental communication during adolescence may help prevent adolescents from choosing early sexual debut and having multiple partners and, consequently, from acquiring sexually transmitted diseases. Efforts are necessary to support parents in their relationship with their adolescent children.