The family is like a sect. You live together and share common values. You have a chief that sets the pace for the rest. In this context you also have family traditions that have been passed down from generations. In some families, there are secrets that everyone seems to know about but no one talks about. Some secrets are openly talked about within certain families whereas in other families it is a taboo. Undying loyalty to family member is the main reasons why some dark secret are never revealed. At times, this is done at the expense and suffering of the whole family.
Mummy Kissing Santa: If you are unfortunate enough to witness your father or mother having an affair, you will be in emotional turmoil for a very long time. Should you tell the innocent partner? It might be easier if you are already an adult and you live away from the family house. You could at least use that as an excuse not to be in contact with your parents. If on the other hand you still live in the same house, you have a moral dilemma. If you tell, you might end of breaking up your parent's marriage. You might also end up get stuck with the guilty parent. If you don't tell, you will have to carry a huge burden for many years. There is no easy solution to this, but keeping silent is not the best option. You are not there to solve your parent's marital problems and the quicker you get things off your chest the better. You could at least let the cheating partner know you are aware of the situation. It is then up to him or her to deal with it. From then onward, your job is done.
Murder she wrote: As gruesome as this may sound, murder can also be a family secret. Some families have conspired to make someone disappear and kept the secret. Rosemary West and her husband were a classic case of murder and secrecy. One kills, the other helps to hide the crime. It is a sort of partnership in crime and secrecy. In such a case, every family member is involved and there is no way any of them is going to call the police. It is like this "if I go down, I'll take everyone with me" . This reminds you of how the mafia operates. You can get in but there is no way of getting out alive. You also have to commit a serious crime that will ensure you will never get the urge to inform the authorities. You could also say such a family secret is like a dangerous sect where the guru brainwashes everyone. Consequently, there is very little chance of the secret leaving the family.
Illegal Immigration: You've heard about arrange marriages and prefabricated love. These types of secrets are not shared with extended family members. You keep the cards close to your chest and pray the authorities wouldn't get their nose into your business. Talking about business, most of those who get involved in this type of secret don't do it for charitable reasons. It is business and you feel you've got nothing to lose. You might even end up finding love. Other family members might be suspicious but there is the rule "don't tell, don't ask".
Gay: How many married men and married women are secretly gay. They might have children and still lead a double life for so many years. This type of secret is easier to keep for some but others just throw in the towel and confess everything. This might mean the end of a long marriage and the beginning of misery for everyone involved.