It is rare but possible for conjoined twins to remain alive and healthy into adulthood, such as is the case with Abby and Brittany Hensel. They have distinct sets of heads, hearts, and lungs. They have two arms and legs and a shared reproductive system. One can be asleep while the other is awake. They have distinct personalities, desires, and opinions.
Suppose there were a set of Jewish conjoined twins in similar circumstances, either male or female. My basic question is this: In terms of halachah, would they be considered one person or two?
There are a range of issues to which this would apply. For example:
- Would they (as men or women) be permitted to marry, and if so, would they marry one person or two, with one ketubah or two?
- As men, would they count as one or two for a minyan or zimmun?
What are some other issues that arise from this situation?