Prayer for requests

Hello Rabbi, I have heard and seen from you in several places that there is no point in praying or that it is even forbidden to pray for requests. The Rabbi cites a source for this from the Gemara, which says that it is forbidden to pray for a change in the sex of the fetus after 40 days of pregnancy, because the sex has already been determined, and therefore it is a former prayer. According to this, it follows that if all science today is deterministic, then it is not possible to ask for anything at all in prayer, because everything has already been determined. I do not understand why the power is deterministic except for human choices. For example, if I see a lion trying to devour a deer, there is a possibility that the lion will succeed and there is a possibility that the deer will run away and it will not succeed. In such a case, one can pray for the lion's success or failure. Why not? The same applies to the sex of the fetus up to 40 days, during which time there is a so-called war over which chromosome will prevail. I would appreciate clarification. Thank you Rabbi, I have heard and seen from you in several places that there is no point in praying or that it is even forbidden to pray for requests. The rabbi cites a source for this from the Gemara, which says that it is forbidden to pray to change the sex of the fetus after 40 days of pregnancy, because the sex has already been determined, and therefore it is a former prayer. According to this, it follows that if today all science is deterministic, then it is not possible to ask for anything at all in prayer, because everything has already been determined. I do not understand why the power is deterministic except for human choices. For example, if I see a lion trying to devour a deer, there is a chance that the lion will succeed and there is a chance that the deer will run away and it will not succeed. In such a case, one can pray for the lion's success or failure. Why not? The same applies to the sex of the fetus up to 40 days, during which time there is a so-called war over which chromosome will prevail. I would appreciate clarification, thank you Rabbi, I have heard and seen from you in several places that there is actually no point, or that it may even be forbidden to pray for requests. The rabbi cites a source for this from the Gemara, which says that it is forbidden to pray to change the sex of the fetus after 40 days of pregnancy, because the sex has already been determined, and therefore it is a former prayer. According to this, it follows that if all of science today is deterministic, then it is not possible to ask for anything at all in prayer because everything has already been determined. I don't understand why the power is deterministic except for human choices. For example, if I see a lion trying to devour a deer, there is a chance that the lion will succeed and there is a chance that the deer will run away and fail. In such a case, one can pray for the lion's success or failure. Why not? The same applies to the sex of the fetus up to 40 days, during which time there is a so-called war over which chromosome will prevail. I would appreciate clarification, thank you Rabbi. I have heard and seen from you in several places that there is actually no point or that it may even be forbidden to pray for requests. The Rabbi cites a source for this from the Gemara, which says that it is forbidden to pray to change the sex of the fetus after 40 days of pregnancy, because the sex has already been determined, and therefore it is a former prayer. According to this, it follows that if all of science today is deterministic, then it is not possible to ask for anything at all in prayer because everything has already been determined. I don't understand why the deterministic force is apart from human choices, for example, if I see a lion trying to devour a deer, there is a possibility that the lion will succeed and there is a possibility that the deer will escape and it will not succeed. In such a case, one can pray for the lion's success or failure. Why not? The same thing applies to the sex of the fetus up to 40 days, during which time there is a so-called war over which chromosome will prevail. I would appreciate clarification, thank you Rabbi, I have heard and seen from you in several places that there is actually no point or that it may even be forbidden to pray for requests. The Rabbi cites a source for this from the Gemara, which says that it is forbidden to pray to change the sex of the fetus after 40 days of pregnancy, because the sex has already been determined, and therefore it is a former prayer. According to this, it follows that if all of science today is deterministic, then it is not possible to ask for anything at all in prayer because everything has already been determined. I don't understand why the deterministic force is apart from human choices, for example, if I see a lion trying to devour a deer, there is a possibility that the lion will succeed and there is a possibility that the deer will escape and it will not succeed. In such a case, one can pray for the success or failure of the lion. Why not? The same applies to sex that lasts up to 40 days, during which time there is a so-called war over which chromosome will prevail. I would appreciate clarification, thank you.