If you get in trouble just say this:

"I was just having fun, i knew they were lying, because while it's true that all embryos start out with a structure that could potentially develop into female genitalia, it's the presence of the Y chromosome (and the SRY gene it contains) which is what determines the development of male genitalia. The Y chromosome isn't added, it's there or it isn't. I was making a similar statement so they could clue in to how absurd they were being."

If you get in trouble just say this:

"I was just having fun, i knew they were lying, because while it's true that all embryos start out with a structure that could potentially develop into female genitalia, it's the presence of the Y chromosome (and the SRY gene it contains) which what determines the development of male genitalia. The Y chromosome isn't added, it's there or it isn't. I was making a similar statement so they could clue in to how absurd they were being."