I'm only taking about a 70-90 year old with an 18-19 year old. When they are old enough to be your great-grandson or daughter, I think it's wrong and disgusting, no matter the gender or etc.
It's very wrong and disrespectful for an 80 year old man to seek for a young girl that's about 18-19 years of age in marriage. I don't like a relationship whereby the guy is far more older than me with 10 or more years.