Will my sperm hurt my pregnant gf baby if ii ejaculate in her whileim currently taking flomax (tamsulosin)?

Not likely: Flomax (tamsulosin) does not affect the quality of sperm, thus should not do harm via the sperm.

No: The only time when penetration is contraindicated in pregnancy is when patient is having contractions, has a discharge of amniotic fluid or infection or if pt is receiving intravaginally medications. The eyaculation will never reach the baby because the cervix is closed with a special mucus that does not allow it to pass.