This story, which admittedly is very biased, says that Oren and Abel were not identical, and weren't even the biological children of their birth parents. They were adopted frozen embryos.
As for the first story, where the woman chose to have her T-18 fetus terminated and "cried afterwards", she also had hyperemesis, and the T-18 baby was quite likely poisoning her in some way, because she said that her nausea disappeared almost instantly after the baby's heart stopped. This was possibly a lifesaving measure for her.