On April 20 (fittingly enough), Canadian Health Minister Jane Philpott announced that legislation to legalize recreational marijuana use would be introduced by spring 2017. Now the speculation on what the government's cannabis regulations will look like have finally begun.

One of the most contentious issues will likely be the legal age. That's because Prime Minister Justin Trudeau has said that he wants to legalize and regulate cannabis to prevent Canadian youth from accessing it. But he hasn't specified what the age restriction would be.

New Brunswick's justice and public safety minister would like to see the minimum age for consuming marijuana set at 21, which is the minimum age in legal U.S. jurisdictions.

Meanwhile, organizations such as the College of Family Physicians of Canada (CFPC) recommends restricting medical marijuana use to patients 25 or older because of dangers that cannabis could pose to developing brains. According to their guidelines, "Youth who smoke cannabis are at greater risk than older adults for cannabis-related psychosocial harms, including suicidal ideation, illicit drug use, cannabis use disorder, and long-term cognitive impairment."

So should the federal government also set the legal age at 25 to keep youth safe? To find out, we contacted activists, advocates, researchers and businesses within the cannabis community to ask for their input. Here's what they said.

1. Canadian Cannabis Clinics (CCC)

Ronan Levy - Director of Canadian Cannabis Clinics - thinks that the government should take the CFPC's lead and set the legal age high.

"Given that the consequences impact developing brains, it makes sense that regulations contemplate restricting it to people at the age of 25," he told the CBC.

However, he's willing to compromise on that position in the interest of curbing the black market for cannabis in Canada. "[The legal age] has to be weighed against the other interest of making recreational cannabis accessible, and if you make it too restrictive, then you risk creating more of a black market."

2. Tweed

One of Canada's prominent licensed producers of medical marijuana agrees that the federal government needs to strike a balance between science and practicality by setting an age limit that keeps youths safe while also preventing a black market from catering to young consumers.

"We of course support an age restriction for recreational cannabis sales to ensure it is kept out of the hands of children," Jordan Sinclair - Tweed's Communications Manager - told Civilized. "Determining the exact age limit must reflect a careful assessment of health impacts, as well as not inadvertently leave a large opening for uncontrolled black market distribution to young people. Nineteen, similar to the age set for alcohol purchase in most Canadian provinces, might strike the appropriate balance."

3. NORML Canada

Craig Jones - Executive Director of NORML Canada - told Civilized, "There are those in NORML who think there should be no age limit, but I'm not among them. I think we have a lot of experience with psychotropics and our history suggests we should probably go with the age of majority [set by provinces and territories]."

That said, Jones isn't confident that setting a legal age will eliminate underage cannabis use. So he recommends trying to restrict access by setting social customs as well as legal regulations.

"I think we've demonstrated pretty conclusively that we cannot effectively PREVENT some trafficking to youth, just as we can't with alcohol....So I think we need to create a social norm around keeping cannabis in all forms out of the hands of kids — the way we imperfectly do with alcohol."

4. The Canadian Medical Cannabis Industry Association (CMCIA)

Cam Battley - Chair of the CMCIA's Advocacy Committee - told Civilized that the CMCIA will defer to the age limit set by provinces and territories together with the federal government, which could be determined based on science, social norms and pragmatics.

"We are cognizant of some research that suggests that there are reasons why young adults should avoid the use of cannabis. And we are sensitive to that. [But] the ultimate decision on consumer access, including age of access, will likely be made by individual jurisdictions, meaning provinces and territories."

"We need to bear in mind that, for practical purposes, provinces and territories might find it difficult to have different ages of consent for alcohol and cannabis, and may decide to harmonize the age of consent for both substances."

And the CMCIA is committed to helping governments gather data to make evidence-based decisions.

"We see as our role at CMCIA as helping ensure that policymakers have all the information they need to establish regulations that are not only effective, but also sustainable. And we're acting as a resource to policymakers on that basis right now... Legalizing consumer use of cannabis is the right thing to do, but it needs to be done in an intelligent and cautious manner. We need to do this in a way that protects consumers and keeps cannabis out of the hands of Canadian youth."

5. Dr. Zach Walsh - Professor of Psychology (UBC)

Dr. Walsh - who leads the University of British Columbia's lab studying the use of cannabis for therapeutic and recreational purposes - told Civilized that legislators need to set the legal age based on social customs dictating when a person is considered old enough to make reasonable choices, not when cannabis use is safe.

"The debate should be based on whether people are able to make a choice for themselves" more so than when cannabis is considered safe to consume, which he argues is still up for debate even though many have settled on the age 25.

"There are a few studies that suggest that adolescents who use cannabis frequently have cognitive development problems, but there are studies that refute that. When we have mixed findings, people tend to stick to the ones that reflect their views."

He added that setting the age limit too high could endanger rather than protect minors.

"If it's too high we're basically just legalizing it for adults and creating more problems for the most vulnerable Canadians. If 18-year-olds are left out, that's creating a black market that would also be accessible to 15 years olds."

And, in general, Walsh argues that regulations should be no more restrictive than necessary. "The bigger picture is making sure whatever regulatory framework we have is not just a step-down from the disaster of prohibition."

The government, he adds, should develop a framework that "respects the rights of Canadians and is no more restrictive than necessary. Whatever restrictions should be based on solid science because a restriction is an infringement on personal liberty. If we're going to restrict that we better have a real good reason."