An Ottawa father has been denied a say in his 18-month-old son's leukemia treatment after he wanted to use hemp oil instead of chemotherapy.

"My fear is that his body is not going to take well to [chemotherapy], and he's only an 18-month little boy," the 23-year-old father told CBC News Monday.

"His body isn't even developed yet, so what happens if this chemo doesn't take well? That's why I was asking for the other ways first."

The man and his 20-year-old wife found out last week that their son has leukemia. The parents and their son can't be identified due to the provisions of the Child and Family Services Act.

Doctors at the Children's Hospital of Eastern Ontario were quick to recommend chemotherapy, but the boy's parents were reluctant. CHEO eventually called the Children's Aid Society after the parents refused to consent to the chemo treatment.

Wife eventually did give consent

Dr. Robert Klaassen, a pediatric hematologist/oncologist at the Children's Hospital of Eastern Ontario, says cannabinoids are useful in supportive care, but not as an alternative to traditional cancer treatments. (CBC) The boy's father wants to use a hemp oil treatment instead. It's something he learned about from his father, who lived next to a man named Rick Simpson, who claims to make a hemp oil that cures cancer and other illnesses.

"If you'd seen what I [saw] in that room with those oncologists and social workers, threatening to steal their son and put him in care and force this treatment upon him without even looking at the science," the boy's grandfather said.

"This violation is not just on my son's rights, it's on every other parents' rights in this country. A parent has the right, and he had the right as a parent, to want a second opinion. That's only the most educated thing to do."

The boy's mother eventually authorized the chemotherapy treatment and the boy is receiving it.

Still, the boy's father said he plans to keep fighting for the right to seek alternative treatment.

Cannabinoids better for supportive, not alternative care, doctor says

Dr. Robert Klaassen, an expert in child blood diseases and cancers at CHEO, said chemotherapy is backed up by decades of research, and that it's important to begin treatment as soon as possible, especially with children.

He said cannibanoids can be helpful in supportive care, especially to fight nausea and help children gain weight, but are not an alternative to traditional treatment.

"I really don't know anything about the efficacy of hemp oil for cancer treatment. We know that we use a lot of cannabinoids for supportive care, and I prescribe it a lot for many of my patients to help them," Klaassen said.

"Quite frankly it's a godsend, so it's not like we shy away from it. But it's really there for supportive care, it's not there for treating the cancers themselves."