Youth is in crisis, all over the world we deplore several problems linked to youth or adolescence: drugs, premature sexuality with its share of consequences, alcohol, delinquency, dropping out of studies, illegal abortions, STDs. After the analyzes carrying out the verification of the hypotheses, we arrived at the following results: The study shows in relation to the knowledge that, 68% of our respondents have a very sufficient level of knowledge, 26.0% whose level is sufficient and 6.0% with an insufficient level of knowledge. This allows us to reject our first hypothesis according to which, the pupils of the terminal degree of Gemena observe a low level of knowledge on sexuality, prevention of HIV / AIDS and STIs; and, this low level of knowledge is due to low life skills education. This, in light of our acceptability criterion of 60% or more. Age (X2: 66.762a; dof: 3; p = 0.000) and sex (X2: 177.344a; dof: 1; p = 0.000) have an impact on knowledge, attitudes and practices in matters of sexuality. And prevention of STIs, HIV / AIDS, because all calculated values ​​are greater than tabular values. The fact of having studied the course of the EDAV has a positive impact on the acquisition of knowledge (X2: 84.017a; dof: 2; p = 0.000), favorable attitudes (X2: 147.890a; dof: 1; p = 0.000) and good practices for the prevention of STIs and HIV / AIDS (X2: 21.782a; dof: 1; p = 0.000); because all calculated values ​​are much greater than tabular ones. We allow ourselves to confirm our second hypothesis according to which there are relationships between the level of knowledge, attitudes and practices of students in terms of HIV / AIDS and STI prevention and the impact (the fact of having studied the course) from life skills education.