The label is actually polysemous and refers to either lack of sexual attraction or a distinct sexual orientation. However, you can use it as a social category in research, but you have to specify what you exactly mean by the word asexual. For more information, the following link can hopefully provide you with the targeted rationale.
Salam Azizam, I think you should provide some information about how sexual behaviour is socially constructed in Iran and supported by the Islamic law and the Iranian cultural views. For example, being sexually attractive or even sexually active for the Iranian young women is a taboo, let alone for the middle aged women. It shows to your readers that the sociocultural contexts of the women's life in Iran.