How are MC4R and fertility related?

The provided context does not contain any information about the relationship between MC4R and fertility. MC4R (melanocortin-4 receptor) is a gene involved in energy homeostasis and appetite regulation. Some studies outside this context suggest a possible influence of MC4R variants on reproductive function, particularly in relation to obesity. However, without specific sources from the given material, I cannot provide an evidence-based statement. The evidence level is therefore marked as unclear.