Your Tanner Stage Calculator seems accurate. Do you have medical training?

Last updated on October 29, 2020


My daughter is two months from 12. I found this site when looking for something to help me understand the timing and tempo of her development. She’s not “the average girl” most books and websites describe. The stage calculator seems pretty accurate, given that I have actual hormone levels from an endocrinologist that put her where your calculator puts her, though her pediatrician puts her further along. (She grew very, very slowly for almost two years before she began to develop at age 10, then grew slightly faster for a year, but nowhere near the average rate of the pubertal growth spurt and not more than she grew during childhood. We are tall people from tall families, and she is not looking like she’s going to grow very much more, according to her pediatrician.)

I’d like to know how you gathered the information you used to develop your rating system and if you have medical training.

Thank you.


I am not educated in medicine, though I have a science degree. Where my talent lies is in research.

It started back in 1990 when I was asked to do a class on sexual issues at the church I was attending that would deal with the immoral ideas being taught in public schools. I realized that the material available wasn’t good enough and ended up writing my own book. I wrote a boy’s book after spending two years researching the available material. I wrote a girl’s book about five years later. Eventually, I put a lot of my writings on the Internet, including the books on sexual issues, and made it known that I would answer questions.

It started slowly, but the number of questions coming in has been rapidly increasing. Each time I get a question I don’t know the answer to, I research it and write back. I believe every question honestly asked deserves an honest answer. I’m just crazy enough to be willing to answer even the embarrassing questions.

The world is full of evil, but I’m hoping that in a small way I can encourage young people to be moral, righteous, and lean upon God’s teachings in their lives. So it seems I’ve come into a role of being uncle or dad to a lot of young people around the world. I get a lot of mail about personal issues which I try to help young people sort through. For some, I’ll chat or talk with them on the phone or through Skype. It takes a good bit of time, but I think every person is worth helping.

The Tanner Stage Calculator came about because of a study that showed that young people performing a self-evaluation of their Tanner stage were basically as accurate as a trained observer. I couldn’t get the material used for this self-evaluation, but I did have files of material that described the various markers in development in detail. I put together a calculator in part because I get so many questions about where a person is in their development. The calculators cut down on these questions and saves my inbox.

Since publishing the calculator, I’ve heard from several doctors that the estimates are reasonably accurate and useful.