Putting the Yahoo in Yahoo Answers

Every once in a while, I mention here that I'm active at Yahoo! Answers and I'll give an example of something of interest to this blog. Well, this is right up our alley.

Wanda asked...

What should I do about my neighbors?

Before you start accusing me of being one of those shrews that meddles in everyone's business without being asked, let me just say in my defense: I never intentionally tried to spy on these people, I just noticed these things by chance.
I just moved into this really small apartment building. There are very few tenants, it's pretty much me, a German old guy living opposite from me, and a brother and a sister just a little older than me living above me, the other 3 apartments are empty.
The German guy is actually really nice and welcomed me into the building, but the brother and sister are strange to say the least. They're hermetical. From what the German told me, the sister has some kind of degenerative disease and the brother is looking after her but they've always lived together. He also doesn't seem to have a job which makes me wonder how they support themselves. I only saw the brother a couple times, going out for groceries, I assume. One time I actually caught him and the sister on the elevator (only time I ever saw her), the poor woman needs a crutch to walk. He then asked her if she wanted him to carry her home so she wouldn't exert herself. I thought it was sweet and didn't think much of it at the time.
Then one night, I was in my room watching TV, when I began listening to noises coming from the bedroom above (their bedroom). I listened, and it sounded like they were having sex. Now before rushing to judgement, I went to their apartment the next day and made up a story that I saw someone I didn't recognize walking the building last night and that I just wanted to be certain that it was someone's guest and not an intruder, an indirect way of asking if they had had company. The brother said 'no, we didn't have anyone over.' then he slammed the door in my face. I've heard the same sounds coming from their room a few times since then.
I'm not sure what to do, I really think they're in an incestuous relationship, should I call the police? But what if I'm wrong, I'll be bothering a disabled woman and her caretaker for nothing. What should I do?

Additional Details

Something else to consider is these are 1-bedroom apartments, so where would the brother be sleeping if not in the bedroom with the sister?

She asked the question in more the one place, and some stupid answers told her to call the police,  but others said she might be mistaken about their relationship or what she heard. Some people were, thankfully, supportive of the rights of the supposed sibling couple.

 Here's my answer...

Don't be cruel. Only if you have reason to believe he's keeping her captive against her will, call the police. Them having sex is not an indication he's keeping her against her will. The sex may have been her idea. From the interviews I have conducted, CONSENSUAL incest between mixed-gender siblings is usually initiated by the female.
That they have sex or make love to each other is NOT a reason to call the police, even if you are disgusted by the thought. PLEASE, either: 1. Leave them alone and mind your own business, or 2. Offer your supportive friendship if they welcome it. DO NOT call the police or tell anyone else about their consensual, loving relationship. It is nobody else's business, would be a waste of law enforcement resources (presuming you live where there are still stupid laws against consensual incest) and then what's she supposed to do? Go live in a hospital???
There is no rational reason for keeping laws or taboos against consensual incest that is consistently applied to other relationships. Personal disgust or religion is only a reason why one person would not want to personally engage in what I call consanguinamory, not why someone else shouldn't do it. An adult should be free to share love, sex, residence, and marriage with ANY consenting adults. Youthful experimentation between close relatives close in age is not uncommon, and there are more people than you'd think out there who are in lifelong healthy, happy relationships with a close relative. It isn't for everyone, but we're not all going to want to have each others' love lives, now are we? If someone thinks YOUR love life is disgusting, should you be thrown in prison?
Some people try to justify their prejudice against consanguineous sex and marriage by being part-time eugenicists and saying that such relationships inevitably lead to “mutant” or “deformed” babies. This argument can be refuted on several fronts. 1. Some consanguineous relationships involve only people of the same gender. 2. Not all mixed-gender relationships birth biological children. 3. Most births to consanguineous parents do not produce children with significant birth defects or other genetic problems; while births to other parents do sometimes have birth defects. 4. We don’t prevent other people from marrying or deny them their reproductive rights based on increased odds of passing along a genetic problem or inherited disease. It is true that in general, children born to consanguineous parents have an increased chance of these problems than those born to nonconsanguineous parents, but the odds are still minimal. Unless someone is willing to deny reproductive rights and medical privacy to others and force everyone to take genetic tests and bar carriers and the congenitally disabled and women over 35 from having children, then equal protection principles prevent this from being a justification to bar this freedom of association and freedom to marry.
Some say "Your sibling should not be your lover." That is not a reason. It begs the question. Many people have many relationships that have more than one aspect. Some women say their sister is their best friend. Why can’t their sister be a wife, too?
Some say “There is a power differential.” This applies least of all to siblings or cousins who are close in age, but even where the power differential exists, it is not a justification for denying this freedom to sex or to marry. There is a power differential in just about any relationship, sometimes an enormous power differential. To question if consent is truly possible in these cases is insulting and demeaning.
Some say “There are so many people outside of your family." There are plenty of people within one’s own race, too, but that is no reason to ban interracial marriage. So, this isn't a good reason either.
Some people who say it is wrong seem to have no problem with complete strangers having sex. So get over it, all of you who want your personal disgust to dictate the lives of others.

I also linked to here.