I didn't mean that it's meaningless because it's harmless, I meant that it is meaningless and harmless.

As for your question, I will have to define some terms so that we're on the same page before answering, so sorry for the incoming wall of text.

First, means of reproduction refers to the resources and tools required for human reproduction. Importantly, when saying "human reproduction", we talk about everything required to make a new human, including everything during and after birth: medical supervision of birth, childcare, schooling, safe home environment, etc. Of course, everything that happens before birth is relevant too – so, e.g., a uterus is part of the means of reproduction concept – but usually people forget about the part after so I address it specifically.

Next, humans interact with the means of reproduction and contribute reproductive labour in order to make new humans. Again, this includes everything after birth too. A guardian helping a child with schoolwork or dealing with an emotionally challenging situation is reproductive labour as much as giving birth is. A teacher providing and controlling the schoolwork is, likewise, reproductive labour.

Looking at human reproduction from this perspective, we can see a complex social organisation with many humans contributing their share of reproductive labour. The way any single human participates in this social organisation is what we call this human's relation to the means of reproduction. Relations to the means of reproduction define various aspects of the social organisation of reproduction, including but not limited to how reproductive labour is divided and who gets to decide when and how reproductive labour is performed.