It is found that male and female adolescents’ self perception on Koh Nipha is not different, however, they would like to have more power for decision making especially the female adolescents. The self-perception of the adolescents on Koh Nipha depends on age group and birth order. The researcher groups the sampling into 4 age groups: 10.00-13.9, 14.0-16.9, 17.0-19.9 and 20.0-22.9. It is found that the group of adolescents at the beginning of the reproductive age, 14.0-16.9, believes that they outclass the other 3 groups. Being the oldest, in between, or the youngest child also affects the adolescents’ self –perception. It is indicated that the self-perception of the middle sons tends to be the most negative whereas that of the eldest daughters and the youngest sons tends to be the least negative. The reason for this is that the cultural expectations are different and it indicates that the different social expectations also lead to different socializing and can cause the children of the same parents to be different in personality. As regards being adults, it is found that, during the present time, there is a difference between the adolescents who mature quickly, the adolescents who mature at the average rate and the adolescents who mature slowly. However, this difference does not continue in to the future. In the first group, “adolescent behavior” starts sooner than in the last two groups. From the analysis, it shows that the structure of self-perception is affected by many related factors: gender, age, family structure, physical development and how they perceive by themselves as adults. (p. 382-390) The results of the research on the self-perception of adolescents on Koh Nipha are evidence of human development. It is the complicated interplay of physical, mental, social and cultural factors and it also represents the dynamic of building growing up and changes in the self-perception of the adolescents on Koh Nipha. Theoretically self imaging, both in physical and mental terms, makes us apparently able to understand and see the relationship between self image and other factors. The adolescents’ characteristics of gender are represented physically, socially and with symbols. It also shows that even though, in Thai Muslim society, men are regarded as superior to women, women do not feel that they are less important than men. In previous research, it was found that women are a gender who prefers competition as much as men and that Thai Muslim adolescent prefer competition more than Thai Buddhist adolescents or Thai Chinese adolescents. Furthermore, the women on Koh Nipha have more power over decision making in economic and social matters and they are also the financial controller in the households. They are strong leader. Both men and women on this island would like to decide everything by themselves, so the power of decision making by their spouse is theirs more and more. (p. 391-392)