Prayer

Hello Rabbi, a friend asked his rabbi if prayer works in nature (the Mishnah in the blessings) and this is what he answered him:
"The claim that because they discovered that the sex of the fetus is determined from the moment of fertilization, this proves that every natural process is deterministic is logically incorrect."
Apart from this, also with regard to the sex of the fetus, the fetus can undergo a morphological change that will change its sex without changing its genetic makeup.
In general, it is known today that there is a certain percentage of non-deterministic processes within nature, so prayer can apply there."

I didn't understand the answer exactly. Can the Rabbi address these claims?