How long does it take for someone to become sterile

[MsSaneJane]

How long does it take for some to become sterile mainly MTF, on a normal HRT dose? I hope I don't get flamed for asking a previously asked question. I tried to search this one.

[fleshpull]

I believe I've read 6-8 months. Keep in mind thats long enough on HRT that you will probably incur other irreversible changes, IE: Breasts.

[pebbles]

It varies but generally your rendered functionally infertile after 3-7days of exposure, Estrogen severely disrupts spermatogenesis.

The infertility becomes irriversible sterility once your testis atrophy significantly from disuse, The the Spermatogoa progenitors will cease division and begin to undergo apoptosis within months without any GNRH or Testosterone... Once large numbers of progenitors are lost the testis cell population can never be restored to normal even  if you stop HRT.
... When this critical loss happens varies from individual to individual some it might never happen. Others within a month or two.

But If I had to put an estimate... 6-8 months.
FYI you will be significantly transformed by that stage anyway.

[Keroppi]

Ultimately, all the answer will come down to YMMV. So, the simple and universal advice to anyone planning on starting MTF HRT (post puberty), store your sperm beforehand. You may never want to or be able to use it, but the option will be there for you.