An example of the absolute nonsense that I think the Mermaids Trainer is talking is the section about fertility preservation. She states that
"Once you are 16, if you’ve socially transitioned at a young age, you’ve been on blocker medication for at least a year to allow you that thinking time, you’ve continued with your assessments with the experts at the clinic, you have your bloods and bones checked regularly and you’ve thoroughly explored your fertility preservation options and preserved your fertility if that’s your wish then you may – and it’s a massive huge may – be offered a very, very low dose of cross sex hormone which will mimic the start of the second puberty."
So she is claiming that these children can go from puberty blockers - to preserving their fertility at 16yrs - and then straight to cross-sex hormones. However these children will not have gone through puberty and this is what the Human Fertilisation and Embryo Authority state about fertility preservation before puberty:
"If you haven’t gone through puberty yet and you’re keen to start hormone therapy or puberty suppressing medication as soon as possible, it may be possible for you to store your ovarian tissue or testicular tissue, which can be collected via a surgical procedure. These treatments are experimental and there have only been a very small number of resulting live births worldwide following replacement of the ovarian tissue. It is unclear at present how stored testicular tissue would be used to restore fertility: this has not been achieved yet. It’s also worth bearing in mind that very few clinics offer these treatments so you may need to travel some way on multiple occasions to have this procedure."
So the reality is that for a female, who has been on puberty blockers and plans to commence cross-sex hormones, the option for preserving fertility is the collection, storage and then experimental use of ovarian tissue (most likely in a surrogate) which has only resulted in a few live births worldwide.
For a male, the option is the collection and storage of testicular tissue, which is so experimental that it is unclear how this can be used to restore fertility.
It is imperative that Mermaids are called out on the seriously inaccurate and misleading information that they are imparting on their courses.