Modern Software Experience


The Men with Thousand Siblings


No, not that kind of sibling torture.
I came across an genealogically interesting story, reported by The Daily Mail, The Telegraph and many other news publications.

mystery masturbator

Barry Stevens, a Toronto film maker, wondered who his biological father was. His mother conceived him with the help of a fertility clinic in England. The clinic did not reveal who the sperm donor was, and Stevens jokingly referred to him as the mystery masturbator. His goal was to find his biological father, to identify this mystery masturbator. London Lawyer David Gollanz also knew he was conceived at the clinic, and likewise decided to try and find out who his biological father is.

The fertility clinic, run by Anglo-Austrian biologist Bertold Wiesner and his wife Mary Barton, promised its clients that all donors were highly intelligent men. That promise alone is a remarkable sales tactic, as it smacks of eugenics. That is especially remarkable when you consider that Mr Wiesner was Jewish and that form many years after the second world war, the practice of eugenics was strongly associated with Nazi Germany.

two thirds

In 2007, DNA tests done on 18 children conceived at the clinic showed that 12 of these, two thirds of them, did not only have the same father, but that their father was Mr Wiesner himself. During the existence of the clinic, some 1500 children were conceived there. If th ratio of two thirds found during the 2007 tests holds for all 1500 children, then Wiesner has fathered one thousand children. So, Barry Stevens and David Gollanz figure that they have one thousand siblings.


This situation raises several issues. It is unethical for a doctor to impregnate women with his own sperm without their knowledge and consent, it is abuse of the delicate position of trust that a fertility technician has. Abusing that trust not once, but hundreds of times to father hundreds of children is creepy.
One may guess that Wiesner had trouble procuring donors for a procedure that was considerably more controversial back then, then it is now, and that he considered himself to be highly intelligent man, but his actions demonstrate street smarts, not real intelligence. A intelligent man would have realised that was creating a serious problem; there are hundreds of people out there who are siblings of each other, without knowing it. The chance of them falling of in love with each other, starting an incestuous relationship, and having children from that relationship is considerably now, and such inbreeding increases the chances of recessive traits in the offspring. Deliberately creating that situation is not intelligent at all.

GEDCOM Torture Test

one thousand siblings

Barry Stevens and David Gollanz figure that they have one thousand siblings. When you have that many siblings, you need a genealogy application to keep track and share the information. You'll probably need it for the birthday reminders alone, and to organise the inevitable Bertold Wiesner Society family reunion, but can a genealogy application handle that? Past torture tests revealed that not all genealogy applications can handle 1200 wives, or 1200 children. The latest GEDCOM torture test file combines both in a challenge to handle 1200 siblings.

Siblings1200.ged in Genealogica Grafica


The latest GEDCOM Torture test is Siblings1200.ged. It is a fairly simple GEDCOM file; One Man with 1200 wives, and one child from each, with the same last name as the woman. This isn't the same situation as the Bertold Wiesner children find themselves in, Bertold Wiesner did not marry all those women; he did not even tell them that he is the father of their child. The man and the 1200 women shouldn't be married, but GEDCOM does not support scientific genealogy, GEDCOM does not even support non-marital relationships, and this torture test file still captures the essence; one man that has children with many women, resulting in hundreds of siblings.

Back in 2010, I created the Married1200.ged and Children1200.ged files by hand. That was done through a lot of typing, copy & paste and last but not least, error-prone search & replace. The Siblings1200.ged was not created by hand, but generated by CreateSiblings, a small throwaway app I created using several parts of GedFan as building blocks. The resulting Siblings1200.ged file is available on the torture test download page.

validated file

The Siblings1200.ged file has been checked by importing it into PAF 5.12.18, Behold 1.04, Genealogica Grafica 1.18.3 and RootsMagic, and by validating it with VGED 3.04 and GED-inline 1.05.

None of these produced any errors or warnings, except Behold 1.04. Behold warned that the date 13 Apr 2012 is non-standard, and should be 13 APR 2012; the warning is that the abbreviation should be in ALL-CAPITALS. That is what the specification seems to say, but it does not; Chapter 2 of the GEDCOM 5.5.1 specification clearly states that All controlled line_value choices should be considered as case insensitive., and that values should be converted to all uppercase or all lowercase prior to comparing. That means that Apr is fine, and that you may even write aPR or aPr.


2012-04-13 instant update

Tim Forsythe was quick to test his AncestorsNow site and fix a small issue.
He has blogged about it and included some C code he used to create larger test files.

2012-04-14 Behold fix

Louis Kessler acknowledged the Behold issue. It is fixed in Behold 1.05.

2013-03-14: Common GEDCOM Identifier Naming Convention

The Sibling Torture Test been updated to comply with the with Best Practices documented in Common GEDCOM Identifier Naming Convention; the identifier for the mandatory submitter record was changed from SUBM1 to U. The file carries version number now.

2013-09-06: header fix

Fixed GEDCOM header issue; WWW record is correct level now. New version number is