Also, in those posts nonbinaryunicorn made this claim:

There are trans men who have begun transitioning that still get pregnant accidentally because it's not very well known that even on T for years you can still get pregnant.

As someone who has closely followed this movement for many years, it's distressing that people within the trans community who I'd hope would be concerned about not promulgating ideas that can put TIFs health further at risk are spreading the notion that "it's not very well known" that girls & women who take exogenous T still can get pregnant & therefore if they have PIV het sex (as many apparently do) they need to use contraception.

Medical providers & the LGBT press have been publicizing the fact that TIFs on T still can get pregnant for many years, & in more recent years this info has also been published on mainstream health sites like Healthline & in mass market publications like The Daily Mail. Even Teen Vogue has run articles with the headline "7 Things to Know About Birth Control If You Are Transgender or Nonbinary - Hormone Therapy Won't Prevent Pregnancy"

For TIFs, female enbies & other female people in the gender identity movement to pretend that information about the high risk of accidental pregnancy - and actual pregnancies - for females taking exogenous T is not widely available and therefore not widely known seems like intentional ignorance. They're basically closing their eyes & sticking hands over their ears and saying "la la la" or "you can't tell me that."

Article in Advocate from 2014: https://www.advocate.com/health/2014/11/10/study-yes-trans-men-can-get-pregnant-despite-testosterone-dysphoria

Online advice column for trans people from 2015: https://www.bedsider.org/features/368-i-m-trans-do-i-need-birth-control

Vice article from 2016 in which a TIF activist says, "the idea that trans men on testosterone cannot become pregnant 'is bullshit': https://www.vice.com/en_us/article/59mbm3/for-trans-men-reproductive-health-is-yet-another-obstacle-to-overcome

Mainstream press article from 2019: https://www.dailymail.co.uk/health/article-6847005/Transgender-men-PREGNANT-year-testosterone-injections.html

Teen Vogue article from 2019: https://www.teenvogue.com/story/things-to-know-about-birth-control-trans-non-binary

Also, a survey of 197 TIFs done in 2018 & reported in the health journal "Contraception" found that, in fact, the majority were well aware that females still can get pregnant whilst taking T. Only 16.4% "believed testosterone was a contraceptive method." A majority of the TIFs - 60.1% - surveyed were using some form of contraception (condoms, pills & IUDs were the methods most commonly used, in that order).

Interestingly, the 197 TIFs surveyed reported 60 pregnancies amongst them - and of these pregnancies, only 10 occurred after testosterone was stopped, & one occurred when taking T irregularly.

https://www.mdedge.com/obgyn/article/169337/contraception/transgender-men-need-counseling-contraceptive-and-reproductive

https://www.contraceptionjournal.org/article/S0010-7824(18)30222-1/fulltext

Current Healthline page about TIFs and contraception that very clearly states:

Men — specifically transgender men — can actually get pregnant, even if they’re undergoing hormone therapy and taking testosterone. Although testosterone can reduce the chances of becoming pregnant, it’s still possible to conceive on the medication.

https://www.healthline.com/health/what-happens-if-a-guy-takes-birth-control

Information showing that TIFs still can & frequently do get pregnant whilst taking high doses of exogenous T is not hard to find. It's freely available to anyone who willing to use the tip of their fingers to type some keywords into a search bar. Or willing to use their voice to ask Alexa.