The extraordinary discovery was confirmed by DNA testing, it left the couple stunned, but they are vowing to stay together and have more children. They both blame the legal system which prevented the young man from being told his true identity until long after his child's birth, because the man's parentage had remained hidden due to the secrecy shrouding Irish family law. .
http://www.news.com.au/world/man-finds-lover-is-his-sister-and-mother-of-son/story-e6frfkyi-1225873799870
In addition to this type of incident, there are occasionally instances of babies switched at birth; although due to increasing care in hospitals regarding correctly identifying patients, the occurrence of this is rare.
For example, there was a case in New Zealand a few years ago it was discovered that two babies were mixed up in a hospital and and went home with the wrong parents. This was only discovered years later through a chance meeting. All over the world, this seems to happen from time to time. One Wikipedia article reports eight known real life cases.
http://en.wikipedia.org/wiki/Babies_switched_at_birth
Some hospitals take fingerprints, foot prints, or palm prints of newborns in order to prevent babies being mixed up. Nurses also double check with the mother, checking the identity of that person as well, in order to prevent errors.
Many hospitals also assign a record number to a baby at birth, and bands with this number as well as the last name of the mother, the sex of the infant, and the date and time of birth are placed on the baby and the mother in the labour ward before the mother and child are separated.
Well-Being Australia chairman Mark Tronson says that, from his pastoral experience, he can imagine there would be emotional turmoil beyond measure, that would be experienced by all concerned, including the child, if a family discovered such a thing happened.
He recalls when his own four children were born, in which he was present for each birth, he watched with an eagle eye ensuring the nursing staff placed the name tag on both arm and leg.
"In my years at theological college in the later part of the seventies, there was a case or two that came to light in the media, and it was discussed in a workshop, what pastoral responses there might be," M V Tronson explained.
The results of this discussion, the pastor should advise the parents at the birth, to check, double check and check again that the tags are firmly in place with the correct name on the tag.
Things can go wrong and mix-ups can happen, and in any process there is the possibility of human error. Tags can be mixed up, especially if nursing staff are towards the end of their shifts and there are a number of births all happening around the same time. So check, double check and check again.