A frustrated mom recently posted on CurlTalk in search of her child’s curl type.

“My 2-year-old daughter has hair that’s straighter in front and tighter in the back,” she said. “When it is drying, the hair looks beautiful. But after a few hours, it puffs up big time. I think she is a 3c or a 4a, and there is a spot in the middle of her back that is kinkier — perhaps 4b. I don’t know!”

Another mom lamented the fact that her daughter — curly at two — now has straight hair.

“I’d looooove to have some of her wave back,” she says.

When the hair begins to sprout from your little one’s head, it can be a confusing mix of curly tufts and frothy waves, with a few straight strands mixed in for fun.

Determining the hair type of an adult can be difficult enough. But for kids, it can an especially complicated endeavor — a task made more difficult by the ever-evolving nature of children’s hair.

During childhood, hair is a work in progress. Ringlets at two may turn straight by four. Stick-straight bobs may go curly when puberty hits.

Follicle shape determines curl type. But the follicle shape can change, and often does change over time.

In general, a child’s hair texture changes every five to seven years, said curly expert Christo of Christo Fifth Avenue in New York.

“The final curl pattern is almost impossible to predict as there are so many factors that affect the hair,” says Jonathan Torch of the Curly Hair Institute in Toronto. “My job is to make sure that whatever the curl type, there should always be a great style to match.”

A CurlTalk mom talked about her daughter’s curls at three, which straightened out until she was 10.

“It started curling and it hasn’t stopped!” she said. “She now has beautiful 3b/4a hair, and I am so jealous!”

Between 13 and 15, the hair goes through its most dramatic changes.

“I have witnessesd all kinds of weird, obscure curl formations and hair color changes during puberty,” Torch says.

The best way to determine a child’s current curl type is to wet the hair, run your fingers through it and allow it to bounce. The texture will determine the best cuts and products for the hair.

“The styling techniques stay the same, but the styling tools must change,” Christo said.