First of all, it is basically forbidden in Islam to look at each other’s private parts, based on Allah’s saying: “Tell the believing men to lower their gaze and be modest. That is purer for them. Lo! Allah is Aware of what they do.‏” (An-Nur: 30), and His saying: “And tell the believing women to lower their gaze and be modest.” (An-Nur: 31). However, Islam does give due consideration to cases of necessity, one of which is medical practice, but necessity is judged according to circumstances that warrant it.
Thus, as a Muslim, if there is no other option for you than attending such integrated classes where sensitive issues are taught as part of your school’s curriculum, then you are excused to do so as long as you are safe from temptation which may arise in such cases.
Here, we would like to cite the following: “All Islamic countries should make efforts to set up schools, colleges and universities for both genders, or make proper arrangements, if this is not possible, to accommodate female students for this purpose. However, the way things stand at the moment, it becomes very difficult for a lady to choose an educational institution particularly at the undergraduate level that is free from this problem. If studying in co-education systems becomes unavoidable, then a lady should try to form a group with other fellow girls and remain in their company as far as possible.”