Even though you can’t RP a child that young I believe when it comes to having kids in game or pregnancy rp it’s more of an NPC thing, right? It adds detail to rp especially at home rp with relationships or friends. You can utilize cim’s or /do’s just to simply put that a child is present, etc. Having a goods item and naming it Child just to show it on your person makes no sense when it’s just a simple /do for acknowledgement that a girl or guy may be carrying a baby etc.
It’s against the rules to rp something that young, yes for obvious reasons. But, if you desire that rp I don’t think it’s dumb or should be limited to simply just not being able to. It’s about being creative with it rply and doing it in the right setting which is more than likely in private with people that you trust won’t take it negatively.