Just to continue the point made by Sapphireflower and boys becoming girls as soon as they start blockers. I was talking with my OH about some interesting court cases. In Croft vs. Royal Mail there was a man who started to transition in his middle age and after working at Royal Mail for some time. They discussed the situation with Royal Mail who were supportive but they asked Croft to use the gender neutral disabled toilets rather than the female toilets (the female staff had complained about him being able to immediately use the female toilets). Croft went to a tribunal and appeal - both of which were found in Royal Mail's favour. Some interesting commentsDealing with gender reassignment, Lord Nicholls first considered biological criteria:
"28. The distinction between male and female exists throughout the animal world. It corresponds to the different roles played in the reproductive process. A male produces sperm which fertilise the female's eggs. In this country, as elsewhere, classification of a person as male or female has long conferred a legal status. It confers a legal status, in that legal as well as practical consequences follow from the recognition of a person as male or female. The legal consequences affect many areas of life, from marriage and family law to gender-specific crime and competitive sport. It is not surprising, therefore, that society through its laws decides what objective biological criteria should be applied when categorising a person as male or female. Individuals cannot choose for themselves whether they wish to be known or treated as male or female. Self-definition is not acceptable. That would make nonsense of the underlying biological basis of the distinction." from the judge in their summation include:
and:
By virtue of the definition in section 82 of the Act, the category includes persons at all stages of gender reassignment under medical supervision but it does not follow that all such persons are entitled immediately to be treated as members of the sex to which they aspire.
and:
To hold that the applicant must still use the male toilets is no less unacceptable than allowing a person, who has been known to the female workforce as a man for many years and has male genitals, an immediate right to use the female toilets. While the good faith of the applicant is this case in wishing to be a woman is not in doubt, the gender test is open to abuse and, quite apart from that, what Lord Nicholls described as self-definition presents a serious practical problem in this context.
I think the idea of 'immediately becoming' the opposite sex is a key issue here and maybe something that we could work from, especially as the above is the current law. In the case of Girl Guiding-at which point do they decide that a boy 'is' a girl.