Twin
One of two offspring produced in the same pregnancy. Use with P31 on items for one twin
Are twins always born during the same year?
Some twins are born right before the New Year, and right after the New Year. There are some twins, implanted through IVF, who are born decades apart.
What external fertilization processes can result in twins? What process can split embryo twins from #1? What process is used to preserve embryos from #1? Is it impossible to apply #2 and #3 to embryo twins created from #1?