Conjoined twins deserve happiness just as much as everyone else. If they wish to marry, they can. Yes, it may be confusing to whomever they marry. However, if the twins' mate (or mates) can accept who they are, then there shouldn't be a problem with it. Laws may have to be interpreted differently when it comes to the marriage or possible divorce, but conjoined twins should be allowed happiness if marriage fits into their plans.
Conjoined twins although they are conjoined are two separate individuals. They have different personalities and even likes and dislikes. They should have the same rights that any other law abiding citizen would be granted. They cannot help that they were born conjoined. They should not be punished and have their rights taken away because of something that is outside of their control.
If a conjoined set of twins finds two people who want to marry them or one of them finds a partner who is willing to enter into this kind of union, then of course they should be permitted to marry. Unless we are willing to separate these twins even if one dies, then each should be accorded full human rights.
Yes, conjoined twins should be permitted to marry, because there is nothing that would disqualify them. A conjoined twin is not someone who is disabled mentally, so there is no reason that they cannot make the decision to marry. It is a bit strange, and poses some practical problems, but it is their right.
Conjoined twins have as much right as any other person to marry, however, I feel that it should only be permitted if both twins agree to it. Otherwise, there is little reason not to allow it. Some feel that it would be too difficult for both twins to agree how to handle something like a marital situation, however, if both twins and the potential spouse feel that they could make it work, it becomes a personal matter between those parties, and no one else really has a place to get involved.