What does 'Note: Repeated classes and/or Skills are highlighted in grey.' mean?

[OriginKenji]

I'm new to Fire Emblem, as Awakening is the first Fire Emblem game I have ever played. I've been trying to make some children, so I went on to this site and don't really know what exactly this means?

Does it mean the classes/skills that the child cannot get?

[Knusperkeks]

I assume you're talking about class overlap for children. This basically means that the class the father is going to pass to the child is already being inherited by it through her/his mother or one of the child's base classes ergo this applies to the classes' skills as well.

E.g. Cynthia already has the Pegasus Knight class from her mother, so this would overlap with the PK that Donnel/Gaius/Robin grant their daughters.

[eclipse]

That's. . .half of it (for the father entries). I'm going to grab Gerome as an example.

Gerome's mom is Cherche, and her class options are Wyvern Rider, Troubadour, and Cleric. Troubadour can promote to Valkyrie or War Cleric. Cleric can promote to Sage or War Cleric. Notice how Trobadour and Cleric share a promotion? That's the second case.