All the findings of the study and all the information gained since, from lone twins meeting through the Lone Twin Network, would confirm that this is an utterly inhumane decision. Surely the twins could be fostered, kept together and brought up in the knowledge that their mother wanted them, but was unable to care for them for reasons beyond her control?
Alternatively, one could be adopted and this too be made known to them both, so that they could meet up later. To kill one off because two cannot be cared for, is to deny the importance of their twinship. The one who is born will never be a singleton and will have the loss of its twin imprinted on it for the rest of its life.