Summary Sexual dysfunctions are a high frequency problem that should be studied because of its significance for individual health. For that reason, approaches to sexuality, sexual dysfunctions prevalence among women and men of a population sample in Mexico City, and the particular frequency of each dysfunction, will convey the possibility of suggesting more precise and focused treatment strategies, as well as the generation of ground lines for the investigation of the specific factors that could be related to them. Based on researches conducted by many pioneers who have approached the study of human sexuality, Masters and Johnson built up, for the first time during the 1960s, the human sexual response and its dysfunctions. Also, they hold the hypothesis that the way to understand human sexuality must relay on the study of the human sexual response cycle. This consists of five phases sexual urge phase, excitement phase, plateau phase, orgasmic phase and resolution phase. Masters and Johnson needed to define those phases, so they described and delimited inherent sexual dysfunctions, which may not always be present -but could be- in human sexuality. In order to give a precise and correct diagnosis, researchers have to define and classify sexual dysfunctions. In this sense, Rubio defines them as "a group of syndromes in which the erotical processes of sexual response are undesirable for the individual or for the social group, and occurs persistently and recurrently". Researchers of the Department of Psychology at the National Institute of Perinatology (Instituto Nacional de Perinatología, INPer) in Mexico City, which is a third level institution (specialties hospital) dedicated to people with reproduction problems, realized that investigation about sexual problems will lead to a broad and objective panorama (not hypothetical) of factors like prevalence, types, and gender comparisons of sexual problems among Mexican population. Main objective. This research seeks to state the prevalence, percentage, frequency, and types of both male and female sexual dysfunctions, as well as the differences between them, in a sample of Mexican population living in Mexico City. The research also intends to analyze some variables related to the sexual life of the population under study sexual information they have previously received, traumatic sexual experiences and childhood trauma. Method (material and procedures) Researchers used the Clinical Record of Feminine Sexuality (Historia Clínica de la Sexualidad Femenina) and the Questionnaire of Sexuality, Male Version (Cuestionario de Sexualidad, Versión Hombres), both validated for Mexican population. The type of study that researchers conducted was populational, screening, descriptive, longitudinal, and retrospective. The study was performed using a non-experimental design with two samples drawn from INPer (patients and others); one of the samples consisted of 384 female participants and the other consisted of 363 male individuals (non partners of the patients included in the sample). Each participant was included into one of two groups Group 1 comprised individuals without dysfunction and Group 2 included participants with sexual dysfunction. This classification was made when individuals were accepted at the INPer as patients, and before they were included in any medical treatment or intervention. Sample size was representative of the number of individuals accepted as patients of INPer that year. Inclusion criteria for men and women consisted of a level of education at least of elementary school -so they could understand the questionnaires- having a sexual partner for a year or more, without previous diagnostic of mental retardation or psychosis, nor medical conditions like neurological or endocrine syndromes, cardiopathies, vascular problems or genital infections, that could influence or determine sexual dysfunctions. Patients were included in Group 1 (control group) without sexual dysfunctions, or in Group 2 (experimental group) with sexual dysfunctions, based upon the results of the Clinical records in women as well as in men, which is intended to determine presence or absence of sexual dysfunctions and the kind of dysfunction that each individual has. The questionnaire, besides classifying sexual dysfunction, explores sexual life. The 10 types of sexual dysfunctions are 1. sexual urge disorder (hypoactive sexual desire), 2. aversion to sex disorder, 3. female arousal disorder, 4, male erectile dysfunction, 5. female orgasm disorder, 6. male orgasm disorder, premature ejaculation, pain associated with intercourse disorder (dyspareunia), 9. vaginism (defined and classified following the Diagnostic and Statistical Manual of Mental Disorders-Text Revised (DSM-IV-TR), and 10. dysrythmia (as stated by Alvarez-Gayou, persistent and recurrent inability to obtain satisfaction in one of the partners due to the difference in sexual urge for sexual activity frequency, when conditions are adequate and the problem is not related to physical problems).

Results:

Prevalence in women was 52%; in men it was 38.8%. Mean in women with sexual dysfunctions was 2.52 dysfunctions by patient; mean in men with sexual dysfunctions was 1.48 by patient. Dysrythmia was the most frequent dysfunction both, in males and females. Concerning variables related to sexual activity, childhood trauma for women, masturbation for men and information about sexuality for both men and women, were the main ones.

Conclusion:

Prevalence of sexual dysfunctions and frequency by patient in individuals attending the INPer is lower in men's population. Having an effective and sound information about sexuality is essential for sexuality development. Another important topic are traumatic sexual experiences that are more frequent in female population and are also associated with sexual dysfunctions; men are less jeopardized for that kind of experiences. Masturbation practice is related to the absence of sexual dysfunctions in men. On the other hand, that practice is not significant for women. Results of this research led us to change attention strategies; this will have a repercussion in the effective treatments and decreased periods of time to solve the problem. Regarding the possibility to generalize the results, research could be directed to determine prevalence in populations with no reproduction risk and then compare them with the population of the study; hypothetically, results would not have a significant variability given the control of variables.