Modesty doesn't changed. That doesn't make sense. modesty is modesty. The principles of modesty don't change. Even angels wore/wear long garments covering arms and legs. When we want to do something that isn't usually acceptable we tend to excuse away our behavior...There's nothing immodest about my stomach...you can only see my cleavage because I'm blessed...the dress is tight because I dried it... and the examples go on and on. I haven't seen anyone reference the "For the Strength of the Youth"... "DRESS AND APPEARANCE: Servants of God have always counseled his children to dress modestly to show respect for him and for themselves. Because the way you dress sends messages about yourself to others and often influences the way you and others act, you should dress in such a way as to bring out the best in yourself and those around you. However, if you wear an immodest bathing suit because it's "the style," it sends a message that you are using your body to get attention and approval, and that modesty is not important. Immodest clothing includes short shorts, tight pants, and other revealing attire. Young women should refrain from wearing off-the-shoulder, low-cut, or revealing clothes. Young men should similarly maintain modesty in their dress. All should avoid tight fitting or revealing clothes and extremes in clothing and appearance. As Latter-day Saint youth, you can also show respect for the Lord and yourselves by dressing appropriately for Church meetings and activities, whether on Sunday or during the week. If you are not sure what's appropriate, ask for guidelines from your parents, advisers, and bishop. " Obviously, bikinis are reavealing and therefore considerd inappropriate attire for young women.