The college's discipline committee determined Thursday Barwin failed to maintain a professional standard of practice and failed to use the correct sperm in insemination cases.
In an agreed statement of facts, five women were involved in four artificial inseminations provided by Barwin between 1986 and 2007 and in all four cases DNA tests confirmed the women received the wrong sperm.
The fifth victim of Barwin's professional misconduct is the sister of a woman whom agreed to act as a surrogate.
Barwin accepted a plea deal that led to two other charges being dropped.
"I regret I've caused my patients any difficulty. My intention was always to do my best for them," Barwin told the panel before his penalty was handed down.
The panel heard Barwin inseminated four different Ottawa women with sperm from men who were not the chosen donors and he admitted to mistakenly mixing up the vials of sperm.
4 mixups span multiple decades
That led to two separate $1-million lawsuits filed by women in 2004 and 2006 that were reported by CBC News in September 2010.
The mothers claimed DNA tests proved the intended donors were not the fathers of their children.
The third incident of mistaken insemination originated in 1986 when a woman alleged her child's DNA did not match that of her husband, whose sperm had been frozen prior to treatment for cancer.
A fourth incident was also revealed at the hearing Thursday, which happened in 1994. Barwin admitted to all four as part of his plea deal.
The two lawsuits against Barwin were settled out of court, so none of the allegations were ever proven until Barwin admitted Thursday to inseminating women with the wrong sperm in four separate incidents.
Barwin has worked at the Broadview Fertility Clinic for more than three decades, during which time he received an Order of Canada and a Queen's Golden Jubilee Medal for his work.
In February 2012, Barwin volunteered to "permanently" stop the "practice of artificial insemination and intrauterine insemination," according to his College of Physicians and Surgeons profile.
Barwin received his medical schooling at Queen's University in Northern Ireland. He is also a past member of the Canadian Fertility Society and the Planned Parenthood Federation of Canada.