Objective: The lack of comfort from physicians is a major reason for sexual health to be poorly addressed in medical consultations. With this study we aimed to explore if medical students, future physicians, already feel uncomfortable to address sexual health when interacting with patients. Design and Method: All students enrolled in Portuguese medical schools were invited to participate in an anonymous online questionnaire between March and June 2015. Students were asked to rate their comfort using a 5-point Likert scale from 1 (“Completely uncomfortable”) to 5 (“Completely comfortable”). Descriptive statistics, factor analysis, Chi-square comparisons and multivariable logistic regression were used to analyze responses. Results: 1872 responses were analyzed. Medical students are less comfortable to talk with patients about Sexual Practices and Relationships (mean=2,96) than Reproduction and Sexual Infections (mean=4,37). Interestingly, the comfort to address both topics tend to decrease along the medical courses (r=-0,161 and r=- 0,083, respectively, p<0.01), in contrast with the increasing comfort to talk about sex outside the clinical context (r=0,100 p<0.01). Students’ main justifications for not feeling comfortable were the fear of letting the patient uncomfortable (29,7%) or offending them (22,6%). Conclusions: The lack of comfort to talk about sexual health issues is a reality when students start to talk to patients, so early tackling of this discomfort is important to improve medical communication in sexual health. In fact, comfort decrease can reveal the transition from expectations to the reality experienced during clinical rotations over the last years of medical education.