(CNN) A Harvard medical pioneer calls it "astounding" — an "incredible achievement" and a "quantum leap forward" in the battle against cancer, autism, Parkinson's and Alzheimer's.

What's going on? Scientists at Ohio State University say they've figured out a way to grow the genetic equivalent of a nearly complete embryonic human brain.

Technically, they're not quite "brains." They're called brain organoids — pieces of human tissue grown in petri dishes from skin cells.

These little blobs of tissue, 2-3 millimeters long, could help researchers test drugs and other treatments that may help prevent, fight and maybe even cure some of the most devastating disorders and diseases of our time.

In addition to Parkinson's disease, autism and Alzheimer's disease, they could also lead to unlocking the mysteries of schizophrenia, epilepsy, traumatic brain injuries and post-traumatic stress disorder. Millions of people suffer from all these disorders and diseases worldwide.

This lab-grown "mini brain" includes most characteristic of a human fetal brain including an optic stalk and a bend in the mid-brain region. (Click to expand.)

"The idea of taking skin cells, reverting them back to a basic stage of development and then teaching them how to turn into the cells that make up the brain is something we have been dreaming about for some time," said CNN Chief Medical Correspondent Dr. Sanjay Gupta. "It is exponentially closer to reality now. Furthermore, the idea of using these 'mini brains' as a testing ground for therapies could help doctors figure out the best treatments for individual patients as opposed to the 'one size fits all' approach that is often used nowadays."

Scientists have been making brain tissue organoids in the lab for less than a decade.

Japanese scientists were among the first to prompt cells from mice and humans to form "layered balls reminiscent" of a part of the brain called the cerebral cortex, according to the science journal, Nature . In 2011, Madeline Lancaster, a scientist a the Institute of Molecular Biotechnology in Vienna, was able to grow an embryonic brain.

Ohio State biomedical researcher Rene Anand said his team's work is different because "our organoids have most of the brain parts."

"I'll give you one example: If you want to study Parkinson's, you need the mid-brain. The best I can tell from all published research on organoids is they don't have the mid-brain. We have the mid-brain we are already moving toward trying to study them."

Anand said he has grown organoids that include 98% of cells that exist in a brain of a human fetus at five weeks.

Photos: Building human body parts Alex Seifalian's lab at University College London helps people who lose body parts to repair themselves by growing new ones . Seifalian calls his lab "the human body parts store." Researchers create new parts with synthetic materials and a patient's stem cells. In this photo, we see a nose mold made of nanocomposite material seeded with cells in a cell solution. Hide Caption 1 of 16 Photos: Building human body parts An ear mold made of nanocomposite material. Hide Caption 2 of 16 Photos: Building human body parts A mold and prototype of a nose. The nostrils will be created later. Hide Caption 3 of 16 Photos: Building human body parts Seifalian leads University College London's Department of Nanotechnology and Regenerative Medicine. Hide Caption 4 of 16 Photos: Building human body parts A lab-grown trachea, or windpipe, inside a bioreactor. Hide Caption 5 of 16 Photos: Building human body parts Researcher Claire Crowley holds up a glass mold of a patient's nose, which is used to create a new nose. Hide Caption 6 of 16 Photos: Building human body parts A nose mold. Hide Caption 7 of 16 Photos: Building human body parts A heart valve made of nanocomposite material. Hide Caption 8 of 16 Photos: Building human body parts Nose molds. Hide Caption 9 of 16 Photos: Building human body parts Crowley works on a lab-grown windpipe inside a bioreactor. Hide Caption 10 of 16 Photos: Building human body parts Nose and ear molds made of nanocomposite material seeded with cells in a cell solution. Hide Caption 11 of 16 Photos: Building human body parts A glass mold of an ear. Hide Caption 12 of 16 Photos: Building human body parts An ear mold in a cell solution. Hide Caption 13 of 16 Photos: Building human body parts Stent made from a nickel titanium scaffold, which will be inserted in a child's artery. The special material is accepted by the body and will expand as the child grows. Hide Caption 14 of 16 Photos: Building human body parts Nose and ear molds. Hide Caption 15 of 16 Photos: Building human body parts An artery is tested using a simulated heard and blood flow. Hide Caption 16 of 16

Creating a fetal brain that includes so many different types of brain cells amounts to a "quantum leap forward," he said. Tanzi co-discovered all three genes that cause early-onset familial Alzheimer's, according to his Harvard biography

Anand said using the breakthrough to learn more about Alzheimer's is a "high priority" for his team.

Despite all the excitement, Anand is quick to point out that the project is still at a very early stage. "The sooner we commercialize it and make a model available, the sooner everybody else can jump in and use it to solve these problems." Brain organoids may help researchers find key solutions to some sub-types of autism within 10 years, Anand said.

"Right now, it's like we're climbing Mount Everest and we're at Base Camp One," Anand said. "You know, you have to stop, get your oxygen together, then move up to the next step. So, we've still got a ways to go."

As you might expect, growing human brain organoids poses a lot of head-scratching questions.

Here are five big ones:

1. Does this mean scientists could grow a miniature version of your "brain?"

Sort of. If a lab technician used some of your skin cells, they could grow an embryonic brain organic that would have your genetic material. Could that brain organoid be developed into a fully grown brain? No, that's not possible yet. A fully grown brain would need a vascular system and other parts before it could meet the official definition of a brain. "They are not capable of growing beyond where they are," said Anand. "We have no intention of going beyond that."

2. Exactly how would brain organoids contribute to new treatments?

Scientists would use them to mimic human brains deteriorating from Alzheimer's or Parkinson's and then study how they react to innovative treatments or newly developed drugs. "You still have to find a way to accelerate the aging of that brain, the pathology, to mimic a disease like Alzheimer's or Parkinson's," said Tanzi.

3. Is it possible that brain organoids are conscious?

No, said Tanzi. Because these tissues don't have any input. "The brain doesn't work alone. The brain needs sensory input. The brain in a dish is not getting sensory input. We depend on our limited sensory system — our five senses — to provide input to the brain. The brain interprets that information and integrates it. And then we're putting everything we experience in context based on the information that's already stored in our brains through synapse."

4. Theoretically, could this research lead to a future with artificially intelligent machines that have humanlike brains?

It's not out of the realm of possibility, Tanzi said. "If somebody someday figures out how to put a brain into an AI that has sensory input — now you're creating AI hybrids with organic brains. Then, that's a whole different story. Then, you're talking about what's been covered in science fiction movies. But I would say it's very far away, if at all."

5. How long will it take for brain organoid research to lead to breakthroughs?

"You need to get this system into hundreds of labs studying these different brain diseases and let everybody take a shot at it. No one lab's gonna do it," said Tanzi. "We can say 10 years, but if you put that brain system and replicate it in the right lab, that could come down to five years. You need experts who know each disease, working in that system."