Semen is not unclean

God hath decreed, in token of His mercy unto His creatures, that semen is not unclean. Yield thanks unto Him with joy and radiance...

-Baha'u'llah (Kitab-i-Aqdas)

http://www.bahai.org/library/authoritative-texts/bahaullah/kitab-i-aqdas/#r=ka_en-1-74

...semen (human) is pure, for you, you are created of this very semen.

-The Bab (Kitab-i-Bayan)

https://www.h-net.org/~bahai/diglib/books/K-O/N/nba/Arabic_Bayan.pdf