To be fair, Seven wasn't a child, she was an adult woman with some basic knowledge of things, likely the knowledge of pretty much every species they assimilated, even if she didn't have the actual experiences. It's not like she was just created right there. She's been alive for about 30 years. Dating her would be like dating a nun, adult one, who has abandoned her vows and she's now free to have a guy. It might be weird, but there is nothing illegal or unethical about it.
Data's daughter was not just days older, which I dn't think it was a big issue. Minuet was hours old, but she was programmed as a mature woman. Lal was also given the body of a teenager, and she acted as one. Data was older than 20 when he had sex with Tasha.
The retarded black fat woman from Academy... I just can't... I don't know what they were thinking.