Even within the same gender, respect for modesty and personal space should be maintained. The Holy Prophet sas said:
A man should not see the private parts of another man, and a woman should not see the private parts of another woman, and a man should not lie with another man under one covering, and a woman should not lie with another woman under one covering.(Sahih Muslim, Book 3, Hadith 90)
As an example, athletes of sports teams showering together would violate the modesty taught in this Hadith.
Also, if there is a dispute between spouses in court, and part of the case depends on determining if the woman was pregnant or menstruating, etc., modesty requires that the court cannot order her to uncover her private parts to be checked by a doctor to confirm her testimony. Hadrat Musleh Mau‘ud ra wrote:
Revealing one’s private parts is only permissible in special cases of illness and similar situations. To uncover one’s private parts to settle financial disputes is not at all permitted. I consider this approach to be completely contrary to Islamic custom, even if some jurist or many jurists may have written otherwise.(Hadrat Musleh Mau‘ud kay Qazai Faisalay
, p. 121, case # 51)
Although generally veiling is between members of the opposite gender, there is an aspect of modesty that deals with veiling between members of the same gender.
One of the purposes of veiling is also to guard ourselves against negative influences, whether they come from men or women. The Holy Quran says that women need not observe veiling from “their women” (نسائهن), which can be understood to mean “decent women” (Holy Quran English with Short Commentary, p. 717).
Hadrat Musleh Mau‘ud ra wrote:
Thus Allah Almighty says that you should first find out about the character of a woman. When you are reassured, then allow them to enter your homes. This is what is meant by “their women.”(Tafsir-e-Kabir, vol. 6, p. 302)
This shows that there is also a type of veiling of women from indecent women by which a barrier of formality is maintained.
As for family, veiling does not apply within
If you want to wear trousers or jeans, your shirt should be long. Some girls think that there’s nothing wrong with wearing a T-shirt or small blouse over jeans in their homes if they wear a long coat when they go outside. Even in one’s home, one should wear modest and appropriate clothing in front of one’s father and brothers. Even though Allah the Exalted has not commanded to do purdah before one’s father and brothers, He has declared the sense of modesty as a part of faith. Also, sometimes relatives or acquaintances can also come to visit your home at any time. Someone might come in the presence of one’s father or brothers, and one may need to go before them, and such clothing might not be appropriate to wear before them. So, in homes, one should dress in modest clothing. Although there’s no need for a hijab [head covering] or dupatta [long scarf ] and you don’t need to cover your head, but even then, your clothes should be modest.(Address to Lajna Ima’illah at Jalsa Germany, June 2, 2012)
Hudur aba said:
The people before whom one can reveal their beauty has been mentioned in detail which includes close relatives, sisters, brothers, husband, father, mother, children. These are the people before whom one does not need to observe the purdah. If one wants to wear make-up then it can be done in front of them and not for anyone else. This has been mentioned in detail in the Holy Quran and has mentioned all those relations [before whom purdah is not needed]. And, even then, the beauty is that which is apparent thereof such as the face, one’s height, physical structure, etc. It does not mean that they should wear fitted jeans and blouse in front of them at home which reveals their body parts. This purdah should be observed even before those who are within the prohibited degree.(Friday Sermon, Jan 13, 2017)
As for family members not exempted from veiling in the Holy Quran, like brother-in-laws and cousins, Hadrat Musleh Mau‘ud ra said:
There is(Farmudate Musleh Mau’ud, p. 342)
veilingfrom them, but it is less than others, meaning that the minimum veiling should be observed.