There are humans born with both sex organs and they are truly transgender https://en.wikipedia.org/wiki/Hermaphrodite#Humans In the past usually the Doctor would do surgery at birth, picking the gender for the child. Some of these kids grew up thinking they were in the wrong body, never knowing they had been born with both male and female sex organs. Many of these kids are born with confusing sex genes and kids without both sex organs can be born with confusing sex genes https://en.wikipedia.org/wiki/Klinefelter_syndrome https://en.wikipedia.org/wiki/XXXY_syndrome They might be XXY, XXXY, or other variations. Since a female is XX and a male is XXY this creates a genetic confusion. Even if born with only one set of sex organs they may feel they are a different sex. However the parent is not in the child's body and has no more right than the Dr to pick a sex or push a child a certain way. These kids are born with a disability just like kids born with an extra chromosome 21 causes Down's syndrome. Different outcome, but none the less a big problem for those born with these different gene counts and sometimes both sets of sex organs. All that said, there does seem to be a genuine transgender ideology agenda to expand what is truly a medical problem into a social problem and kids are paying for it. http://dailycaller.com/2017/07/03/mother-wants-to-record-babys-gender-as-unknown/
We ought to be able to separate real issues from false issues, scientific health issues from social fads.