Is there any objective value of having your biologically own kids?

Imagine if you are married and want to have kids, and you have a friend who clearly has better looks and/or health than you or your spouse. Would you like to ask them to provide egg cell or sperm? Why not?

What's the value of true lineage for humans who can select using human mind, not only being led by instinct? Is selfishness the only reason to have your own biological kids or there's something else?