Jodie Patterson's 3-year-old, Penelope, was brooding and angry until one day she asked her child what was wrong.

Penelope, who was assigned female at birth, was upset "because everyone thinks I'm a girl," but he said he was really a boy.

"I said, 'However you feel inside is fine.'" Patterson recalled from their home in Brooklyn, New York. "And then Penelope looked at me and said, 'No mama, I don't feel like a boy. I am a boy.'"

Almost immediately, Patterson embraced the reality that Penelope was a transgender boy, and by age 5 he was going to school as a boy. Today, at age 9, Penelope is happy and healthy as a boy who loves karate and super heroes and decided to keep his birth name.

Increasingly across the United States, doctors and parents of transgender children are embracing their identity as soon it starts becoming obvious, sometimes around age 3. Many say they are finding much greater chances of happiness and well-being when children are nurtured in their new gender identity at such a young age.

Although there is not a consensus on the issue, some clinicians who work with transgender children have concluded that when children persistently identify as the nonconforming gender, the best course is to socially transition, or live as the other gender, even at age 3.

Other specialists in the field advocate a more cautious approach because the long-term psychosexual results for young children can vary widely and unpredictably.

In Penelope's case, his behavioral problems disappeared as soon as his family affirmed his new gender identity, said Patterson, who has five children. "That whole grumpy face became happy face," Patterson said.

Whatever the age, parental support is crucial.

Fifteen percent of transgender Americans say they ran away from home or were kicked out of the house, according to a survey released on Dec. 8 of nearly 28,000 transgender adults.

The same study, by advocacy group the National Center for Transgender Equality, found transgender adults were nine times more likely than the general population to attempt suicide.

But transgender people with supportive families were far less likely to attempt suicide, be homeless or experience serious psychological distress - by nearly 20-point margins compared with those who lacked family support, the survey said.

With better education, today's transgender children generally receive much more support than those surveyed adults did in their youth.

The question remains, though, around embracing gender nonconformity: How young is too young?