This question is URGENT: My parents are concerned with my swimming, so they want me to join the swim team this summer. It is mixed swimming, so women are going to be there, and I am a boy, so I do not feel comfortable going. What is your personal opinion, and halachic opinion on this? Again...an answer is urgently needed!

ב"ה Shalom The Halacha is very clear on this. One may not swim where this is mixed swimming. See Shulchan Aruch Even Ha'aezer 21, Rav Moshe Feinstein zt"l (Igrot Moshe Even Ha'ezer vol.1:56, ), Rav Shmuel Wosner zt"l (Shevet HaLevi ol. 3 : 185, Rav Ovaddiah Yoseph zt"l ( Yechaveh Da'at Vol. 1: 38, Vol. 5 ;63) and many others. In addition, one may not listen to his parents when they tell him to violate Torah or Rabbinic laws. (Shulchan Aruch Yoreh De'ah 240: 15) However, even in this situation in which they are asking to do something in conflict to Halacha, you must behave appropriately. Therefore, you must find the most proper and pleasant way to explain to your parents why you cannot go mixed swimming. Depending on your age and/ or background, you may want a school teacher or another adult to assist you in speaking to your parents on this issue. All the best