I used to work for a woman that swore ACV, when fed to brood mares would make them have fillies. She said it had something to do with the alkaline levels of the body would not support a colt. I don't know if it is actually true or not. But I can tell you that she only had one colt while I was working for her, and it was out of a mare that she sent off to be bred, and they didn't continue the ACV regimen while she was there. All the rest of her foals were fillies.