"Modern Family" focuses on three separate households, all related to one another to create one big "happy" family for television of today. One of these three families focuses on the relationship of a gay couple, Mitchell and Cameron, and their new journey after adopting their daughter Lily.
http://beta.abc.go.com/shows/modern-family/bios
http://beta.abc.go.com/shows/modern-family
"Grey's Anatomy" takes a different approach by showing the growth of a seemingly straight female character named Calli, into accepting herself as bisexual half-way through the show's timeline, and eventually marrying the love of her life, a woman and fellow co-worker, Arizona. The two face love, happiness, turmoil, scrutiny, dis-owning by family, break-ups, and even a pregnancy that forces them to realize what's important in their lives and eventually owning up to their mutual want to be mothers for that child.
http://abc.go.com/watch/greys-anatomy/SH559058?CID=google_sem_1