Introduction

Puberty is a stage of human growth and a natural event accompanied by hormonal changes in the body controlled by the brain. At this stage, sex organs develop, and secondary sexual characteristics emerge (1,2). In many families, girls and boys do not have enough knowledge about sexual development and characteristics related to their sex and the opposite sex (3). Lack of awareness and developmental preparedness in adolescence leads to various problems along with confusion (4,5). Among the most important characteristics of this stage are awakening sexual energy and attention to the opposite sex. The teenagers' attention to the opposite sex is not always due to sexual enjoyment; rather, it can be out of the need for kindness or praise and mature expression (6,7). Physical and sexual abuse can be observed among girls and boys across different ages, all ethnic groups, and socioeconomic levels (8). Sexual abuse includes a spectrum of forced sexual activities that usually occur for various reasons in early adolescence (ages 11 to 15 years). Sexual abuse means forcing a person to perform a sexual behavior that she does not want to do and is not able to resist physically or mentally for various reasons (9).  
Most boys and girls with mild intellectually disable (MID) enter puberty and go through other developmental changes similar to normally developing individuals. In this period, the secondary sexual characteristics emerge and get activated, which is quite significant in MID adolescents. Due to low IQ, these individuals face more challenges and are deprived of educational resources requiring mental power. Additionally, they are often deprived of parental support and training to adapt to the new period (4). Therefore, the risk of being exposed to sexual abuse intensifies in such adolescents (6,10).
Studies have revealed that knowledge about sexuality in ID adolescents is less than their normal peers. They have incorrect, inappropriate, and ambiguous information about sexual issues, sexual deviations, and sexually transmitted diseases. The reasons for their limited knowledge are their insufficient social and verbal skills (11, 12,13).
Results obtained from various studies show that the risk of sexual abuse in adolescents with ID is more than their normal peers. Children with ID are at greater risk of sexual abuse because of certain reasons such as dependency, belonging to others, naivety, and lack of knowledge on sexuality. Furthermore, most individuals with intellectual disabilities experience some form of sexual abuse in their lives (10, 11). The vulnerability factors of teenagers with intellectual disability towards sexual abuse can be grouped into three broad categories: individual, family, and community (14). Individuals with disabilities experience violence in their lives. Teenagers with an intellectual disability are not immune to sexual abuse, and more research is needed in this area (12).
Generally, children and adolescents with intellectual disability are unable to protect themselves against the abuser due to a number of reasons listed below:
Lack or limited knowledge of sexual identity and sexual role (refers to a cultural expectation on how men and women communicate with each other and Gender role is associated with sexual identity), lack of awareness of sexual issues, inability to learn the rules of society about sexual behavior, lack of exercising proper judgment, diagnosis and assessment of the annoying situations, lack of awareness of illegal nature of sexual abuse, lack of understanding the physical and psychological consequences of sexual abuse resulting from intense fear, an emotional attachment to the abuser, lack of training by family and school as the most significant cause, and inadequate ability or skill to protect themselves against the abuser (6, 15). The protective strategies should be taught to the girl adolescents with MID; otherwise, the risk of sexual abuse may increase as they get older and less relationship with parents and caregivers. Unfortunately, many educational programs encourage children and adolescents with MID  to accommodate different life situations (16).
Dionne & Dupras, 2014, point out that intellectually disabled individuals should be trained on preventing pregnancies  , sexual harassment and, Sexually transmitted diseases. Their intellectual restrictions make them vulnerable to these dangers (17).
In a study conducted by Soylu et al., 2013 it was revealed that the group with ID had different sexual abuses, including penetration and contact. The abuses were confirmed through their reports at a later period with a lower rate. Also, post-abuse pregnancies were more frequent (18).
Sexual abuse may be diagnosed hardly, and there is often no conclusive evidence to confirm it (19). Such symptoms include wounds, bruising and discomfort in the limbs or genitals, torn or missing clothes, sexually transmitted infections, bone fracture, ecchymosis, pain and itching in the genital area, bleeding in anus or vagina, frequent urinary infections, abdominal pain as well as difficulty in walking and sitting. The above cases should arouse suspicion of sexual abuse (20).  
Sexual abuse results in certain physical, behavioral and mental disorders. Sexual abuse leaves large effects on the lives of young people with ID and can lead to permanent post-traumatic stress disorder (PTSD) (21,22). Such individuals may experience fear, anger, sleepwalking, loss of interest in previous favorite activities, depression associated with shame, guilt, a sense of permanent harm, isolation, avoidance of certain environments or people, continuous crying, eating disorders, and academic failure, among others (8, 23, 24).
Research findings indicate that adolescents with MID have limited information about sexual issues and cannot recognize proper from improper requests making them more susceptible to sexual abuse (25). To make MID adolescents aware of private space, we should hold self-defense classes in schools to provide the necessary training. The continued growth of self-esteem and interpersonal skills can evoke positive feelings for adolescents. Additionally, being exposed to emotional support from family and friends enables them to feel that they can protect themselves and their rights (26).
Therefore, it is important to pay attention to sexual abuse in adolescents with the intellectually disabled. Given the importance of sexual abuse in puberty, the aim of this study was to determine sexual abuse among mild intellectually disabled teenagers in puberty. The following questions will be examined:
First question: How many adolescent girls and boys with mild intellectually disabled were sexually abused?
Second question: What are the symptoms and consequences of sexual abuse in girls and boys with mild intellectually disable who were sexually abused?
Methods
The present study was a descriptive cross-sectional,   study that was carried out in Yazd, Iran. The purposes of this research were to examine the prevalence and symptoms of sexual abuse in girls and boys with mild intellectual disability (MID) in puberty.
The statistical population consisted of all boys and girls with mild intellectual disabilities between 12 and 16 from exceptional public schools and their mother, Yazd, Iran.  The research sample included 150 girls and 150 boys with mild intellectual disabilities (MID), who were selected through cluster sampling with the formula: p=0.12, d=0.2P, and α=0.05 (27).
  
To select samples, of each region, one school of students with MID was selected, then from each school, the number of classes and then a number of students were selected randomly. Inclusion criteria contain students (boys and girls) with mild intellectually disabled, IQ=50-70 (with WISC-IV), and 12-16 years old, who had not experienced precocious puberty.
Research tool
To assess sexual abuse in girls and boys with MID a self-designed questionnaire was used, and it comprised two sections. The first section was on the participants' biodata, including the adolescent's age, the family's income, the average educational scores, the number of family members, and the mother's educational level. The second section consisted of the 15-item questionnaire about sexual abuse knowledge (meanings and signs of sexual abuse, get training, identify situations where there is a possibility of sexual abuse and defense skills) of boys and girls with MID and 35 dichotomous questions probing symptoms of sexual abuse in the two gender groups. The questionnaires were completed by the participants who merely provided a 'yes' or 'no' response coded as 1 or 0.
The validity of the questionnaire was established through content validity measured by Lawshe's method. This method is among the quantitative methods of content validity. The questionnaire items were first examined by several university professors and experts in the field. Then, the index for content validity ratio (CVR) was calculated for each individual item through the following formula, and finally, the required modifications were made. In this study, using the Spearman correlation coefficient, the reliability was obtained through a test-retest method with a 2-week interval for both groups. The coefficients obtained for boys and girls were r = 0.81 and r = 0.83, respectively, and the values were significant at α = 0.05 level. To determine the internal consistency, the Kuder-Richardson formula was used. In this method, the internal consistency of the whole test is examined, taking into account all items of the test. Using the Kuder-Richardson coefficient, the obtained coefficients for boys and girls with MID turned out to be 0.80 and 0.84, respectively.
The purpose of the research was explained to the subjects by the researchers. The participation of the samples was voluntary and their response was confidential.  
The questionnaires were given to the students' mothers, followed by some clarifications on the objectives and significance of the research and the method of answering the questionnaire items. The section on sexual abuse knowledge was completed by boys and girls with MID along with the guidance of the researcher. With the help of researchers and an individually15-item of the questionnaire about sexual abuse knowledge completed by teenagers. To complete the questionnaire by adolescents, the questions were stated simply and understandably by the researchers. It is worth mentioning that in cases of experiencing sexual abuse, the mothers were asked to answer the items related to sexual abuse symptoms.
All statistical assessments were frequency, percentage, Spearman correlation coefficient, and ( P < 0.05) was considered significant. The data were analyzed using SPSS statistical software (version24).
Results  

1. about 45% (n=67) of the subjects were boys, while 40% (n=60) were girls with MID at the age of 13. About 43.33% (n=65) of the boys' mothers and 41.33%( n=62) of the girls' mothers had a high school certificate. Also, 60% (n=90)  of the boys' parents and 55.34% (n=83)  of the girls' parents pointed out that their children had not received any training on sexual abuse by family and schools. Table 1 shows the number of people who have been sexually abused.

In response to the first research question, results show that (table 1),  2.67% (n=4) of the girls and 4%(n=6) of the boys were sexually abused in different ways, and they had not received any training on sexual abuse by family and schools.
In response to the second research question, table 2 depicts the symptoms of sexual abuse in girls and boys with MID that were sexually abused (Girls: n = 4, Boys: n = 6).

2. Results show that (Table 1), the symptoms include (depression, isolation, anxiety, aggression, avoiding certain environments, avoiding certain adults, continuous crying, sleep and eating disorder, sudden academic failure, and sexually inappropriate behavior (are visible to girls and boys who have been abused. Table 3 depicts the correlation coefficient between sexual abuse knowledge and demographic information.