I read with great interest the letter penned by Rinaldo de Gallo III (Jan. 1) regarding the offspring of Cara Rafaela. The dam of Bernardini was euthanized last week because of the infirmities of old age. She was 23.

Cara Rafeala (Quiet American) was bred to Tapit, his grandsire A.P. Indy and A.P. Indy's sire Seattle Slew.

Gallo asks since she produced foals from the same sire line are the foals considered more than half-siblings? Are they, he inquires, three-quarter, five-eighth or even nine-sixteenths “in blood.”

He also notes that Cara Rafaela's full sister, Well Related, had offspring by A.P. Indy and Tapit…thus are those foals more closely related.

This interesting question has been debated by Thoroughbred breeders for many years, and I personally examined it twice while at The Blood-Horse.

When I joined the publication in 1992 as Research Director, it was still researching the statements claimed in every single advertisement. As part of that exercise, the publication consistently made advertisers change the wording every time they claimed foals to be anything other than full or half-siblings, which was the editorial policy.

Years later, as the Executive Editor, I oversaw the updating of the magazine's stylebook, which covered not only things like punctuation and grammar, but more importantly points that covered styles specific to the Thoroughbred industry. Things like whether foals could be more than full or half-siblings.

I discussed this, and many other subjects related to breeding, with John Gaines, who had a fascination with genetics. Gaines, who died in 2005, took over a successful Standardbred operation begun by his grandfather and began a Thoroughbred division of Gainesway Farm in 1962. Gaines endorsed the publication's position, he explained to me, because no one could agree on what defined a three-quarter sibling.

Is it when a mare is bred to a sire and that sire's son? Is it when a mare produced foals by full brothers? What about full sisters bred to full brothers? What about half-sisters covered by the same sire?

Two foals by the same sire and dam are full siblings. Two foals out of a mare by any two stallions are half siblings.

That we can agree on.

Anything else is just fodder for an interesting discussion.