I don't know. That's why moral theologians make the big bucks.
This is just smoke produced by those who serve another Master.
It's a moot point. Apparently the "fetus" was dead. Here is the BBC reporton this story.
A seven-year-old boy who was admitted to hospital with stomach pains was actually "pregnant" with his twin brother.
Doctors at Chimkent Children's Hospital in Kazakhstan originally believed Mourat Zhanaidarov was suffering from a cyst.
But during surgery, they discovered he was in fact carrying the dead foetus of his twin brother.
The foetus had developed into a tumour but was found to have hair, nails and bones.
'No longer alive'
Doctors at the hospital told the BBC the tumour was the remains of his twin brother's foetus.
They said that while it was no longer a living substance it was feeding off the boy's blood supply.
If left unchecked it could one day have threatened Mourat's own life.
In this case, I believe Moral Theology would say it is licit to remove the fetus from the boy and see if it survives on its own. By all means, such unborn children should be baptized straightaway as soon as the host-child is opened up, and even before it is removed.
Technically, I wonder if this a fetus?
According to Heribert Jone's Handbook of Moral Theology, when there is any doubt in the case of monstrous forms, anything that appears to be a second child should be conditionally baptised.
So, apparently, it was a direct attack on the fetus.
Not necessarily any more than surgery to seperate conjoined twins is an "attack" on one of the twins, especially in those cases shortly after birth where one of them is sure to die from hydrocephaly and the like. This is an extremely rare and bizzarre case of conjoined twins.