There is clear evidence that EM patients have defects in eutopic endometrium, including differential expression of key endometrial receptivity markers such as leukemia inhibitory factor (LIF), protein arginine methyltransferase 5 (PRMT5), and homeobox protein hox-A10 (HOXA10), that have been associated with EM and subsequent infertility (Cai et al., 2022; Tomassetti and D’Hooghe, 2018; Zutautas et al., 2023). This evidence concerns the gene LIF and erythema multiforme.