Ethanol-5 and Lemon-7, strictly speaking, weren't really in a boyfriend-girlfriend relationship.
Because Synthetic Humans simply don't possess the capability to reproduce... Such a relationship doesn't exist at the design level.
Their bodies don't contain a single piece of real flesh and blood, let alone the genetic material necessary to bear offspring.
Synthetic Humans have different gender identities and individual differences, solely because humans have these distinctions.
After all, the essence of Synthetic Humans is to be the laboratory version of the "shell" meant to house downloaded consciousness for future human use. By design, they're not intended and not allowed to create offspring without systemic permission—this would be considered unauthorized self-replication, a viral behavior.