Scan pic confusion.

This is a my scan picture. The baby was measuring 11 weeks. I'm just confused what the shape is under its buttox, between its legs. Is this testicles or a penis? Tail bone? Placenta? The ultrasound technician said the baby wasn't fully formed and it was impossible to tell the gender due to the genitals not being developed as if it.  Just want to know what that thing between the legs is? Any ideas? Thanks