oomis – thank you! you answered a question I had in the Gemara!
In Brachos (Samech amud Alef) that from 3 until 40 days one should daven that it (the embryo) should be a boy.
Knowing that gender was decided at conception I had did not know how to understand the gemara. Now I know, if it is supposed to be a male you must daven that everything forms correctly and it does not remain a female.
Yasher Koach!