As far as birth control - the sad reality is that contraception leads to abortion because abortion becomes the "backup plan". In at least one study, over half of women seeking an abortion WERE using birth control. I have heard - from the women themselves - of women who got pregnant while using TWO types of birth control
As with other posters these women (and presumably transmen) did not wish to get pregnant did their best to prevent it and had a termination when those preventatives failed. Also, the study you cite which is it? Who carried it out? The premise sounds very spurious, as any researcher knows correlation does not imply causation. But since anecdotal evidence seems to be your stock in trade, as someone who has enjoyed sex since my teenage years, quite a while ago btw, and has been fortunate enough to never have an unwanted pregnancy, I can assure you that contraception when it works is fine.
The method you cite is not known for its reliability
FAMs are about 76-88% effective: that means 12-24 out of 100 couples who use FAMs will get pregnant each year, depending on which method(s) are used. If you use multiple FAMs together, they work even better.
The better you are about using FAMs the right way — tracking your fertility signs daily and avoiding sex or using birth control on “unsafe” days — the more effective they’ll be. But there’s a chance that you’ll still get pregnant, even if you always use them perfectly.
Fertility awareness methods don’t work as well as other types of birth control because they can be difficult to use. Want a more effective way to prevent pregnancy? Check out IUDs and implants, or take this quiz to find the birth control method that’s best for you.
www.plannedparenthood.org/learn/birth-control/fertility-awareness
Additionally the small percentage of people who don’t’ use or have no access to contraception account for half of those who have unplanned pregnancies, which directly contradicts your claims
About 90 percent of sexually active women use some form of contraception. The 10 percent of women who do not use contraception account for approximately half of unplanned pregnancies, but the other half occur in women who were attempting to use some form of birth control.
shriverreport.org/why-are-50-percent-of-pregnancies-in-the-us-unplanned-adrienne-d-bonham/