Last week we got a look at the underside of Donald Trump’s hairdo. What we saw only added more fuel to the proverbial fire that is the Trump hair debate. Is it real? Is it fake? Why is it that color? These are questions that plague the brightest researchers and scientists, and now two plastic surgeons are weighing in by sharing their thoughts with The Daily Beast.

The clip of Trump boarding Air Force One now has millions of views on YouTube. Rumors that the president had a scalp reduction operation in the late ‘80's once again gained traction as a result. The procedure was used during that era to reduce bald spots by pulling pieces the scalp forward.

According to The Daily Beast, in divorce paperwork from Trump’s ex-wife, Ivana, asserted that a plastic surgeon operated on Trump. The alleged surgeon Steven Hoefflin's patients also included Michael Jackson, Joan Rivers, and Elizabeth Taylor. Trump denied the claim in 1993.

One professor at Johns Hopkins told Daily Beast that she doubts Trump underwent scalp reduction surgery, but that he could have had a hair transplant. “If you had a large bald area, you’d have to have several procedures in a row before you actually achieved your goal to cut out the bald spot. You can’t do it in one fell swoop,” Dr. Lisa Ishii said. “It’s such an outdated procedure. It’s possible that he had a hair transplant.”

Hair transplants are different from scalp-reductions but aim to achieve the same goal. Instead of pulling the scalp, a hair transplant involves taking hair from somewhere else on the body and putting it on the bald spot. Dr. Samuel Lam owns a hair restoration clinic in Texas and says that though hair transplants are less invasive, he thinks Trump had a scalp-reduction surgery.

“If you see a vertical incision on the back of the scalp on the crown, that’s very typical of a scalp reduction,” Lam said. “Most likely, he [Trump] had it.”

It’s hard to tell from the video if there is a noticeable incision on Trump’s scalp or just an empty bald spot. Some are arguing that the proof is there, while others just took the Air Force One fiasco as an opportunity to drag the Cheeto-in-Chief. For now, at least, it seems that the comb-over mystery remains.