How a child misses biological parents

I wonder if children of single parents miss their 'other' parent. I wonder if two dads, or two mums, can make up for the fact that the other biological parent (of the other gender) is not known/around. What if the missing parent is the same gender as the child; can a boy raised by two lesbians feel the lack of a leading man?

What about adoptions and egg/sperm donations? Do those children ache to know the people with whom they have a genetic connection?

This article goes someway to look at the very real pain children can feel at a missing part of their life. For this little boy he remembered a father and knew his mother prevented them from seeing one another.

So do you miss what you never knew you had?