How does one use subterfuge regarding a bechor? [Concerning] an animal that was pregnant with her first offspring, one declares, “What is in this one’s womb, if [it is] a male, it is an olah,” [if] she gave birth to a male, it is offered as an olah. And [if he declares,] “If it is a female, it is a shelamim-offering,” if she gave birth to a female, it is offered as a shelamim. [If one declares,] “If [the fetus] is a male, it is an olah, and if [it is] a female, it is a shelamim-offering”: [If] she [then] gave birth to a male and a female, the male is offered as an olah, and the female is offered as a shelamim.

If she gave birth to two males, one of them is offered as an olah, and the second one is sold to those who have an olah obligation, and its proceeds are chullin. If she gave birth to two females, one of them is offered as a shelamim, and the second one is sold to those who have a shelamim obligation, and its proceeds are chullin.  [If] she gave birth to a tumtum or an androgyne, Rabban Shimon ben Gamliel says: No sanctity takes effect upon them.