I don't think either is rude/impolite. There are tons of reasons why it's acceptable but to name just a few scenarios:1) everyone likes a gender reveal.2) some people dont plan a second, third, fourth kid and get rid of all their baby stuff then... oops... now they new more stuff. 3) there are some people who have 3 boys and have a fourth trying for that girl and vice versa so of course a baby shower is warranted. 4) then there are the people who have a baby thinking it's there last and get ride of everything. 5 years later (or any # of years) or even a new relationship later decide to have another and need more stuff. 5) then there are the unfortunate ones who have lost everything due to unforseen circumstances (i.e. fire, bankruptcy, loss of job, other natural disasters or financial hardships) where they need more stuff even if their kids are super close in age or have an age gap. 6) and finally people with multiple kids who have very used baby items that have lived past their life. A new car seat should be bought with each new kid even though lots of people reuse them. A stroller that has survived through 3 kids probably needs to be replaced. Baby clothes get stained easily if not washed properly so most will probably need to be replaced by the 2nd or 3rd kid. Ect, etc, etc. Reasons why it's not acceptable? I can only think of one and that's if you still have everything from your 1st kid AND it's still in pristine condition. I can see wanting to "upgrade" certain things but people in general tend to have different definitions of "need" vs "want". Jmo.