"Can an mtf trans women get an ftm trans guy pregnant?"
Both would have to be pre-op and NOT on hormone replacement therapy (HRT).
If either is on HRT the odds of pregnancy go down dramatically. Estrogen can make trans women sterile in as little as 6 months and testosterone usually shuts down a trans man's ovaries in a month or two (no more periods).
If either of them has FULLY transitioned then it's impossible. Once a person has fully transitioned they are permanently sterile. *
* Unless genetic material (sperm/eggs) was stored before to be used with a partner or surrogate.
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