What is allowed from a female's body to be shown to her son, brother, father, or other family and relative members? Does a female have to be careful of her men relatives, so she will not be a victim of sexual aggression? How should she avoid such sexual chances with young or old men from her family members?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

It is permissible for a woman to uncover before her Mahaarim (plural of Mahram) those parts of her body which generally appear such as neck, head, palms, feet and the like. The evidence for this permission is the Saying of Allah (which means): {…and not expose their adornment except to their husbands, their fathers, their husbands' fathers, their sons, their husbands' sons, their brothers, their brothers' sons, their sisters' sons, their women, that which their right hands possess, or those male attendants having no physical desire, or children who are not yet aware of the private aspects of women. And let them not stamp their feet to make known what they conceal of their adornment.} [Quran 24:31]

Allah has permitted a woman to uncover her adornment to the mentioned relatives in the verse. This permission is conditional when the woman or her Mahram does not feel any temptation; if both of them or one of them feels temptation, then uncovering herself in front of such a Mahram is not permissible. Know that only looking with lust is a kind of Zina as mentioned in a sound Hadeeth. So, any kind of Zina with a Mahram is more repulsive.

Therefore, if a woman or her Mahram fears temptation then she must cover herself as she covers herself from non-Mahram men. It is strictly forbidden for her (or anyone else) to expose herself to what is forbidden.

Allah knows best.