The subject question is very complicated and difficult to give a definitive answer. It might be simply asked, why would God create man at all? The real problem is that we do not know the precise answer to those questions. We can, however, find clues to possible answers in the Holy Bible for the reasons. But first, we have to remember the statement from God Himself through the prophet Isaiah:
"For my thoughts are not your thoughts, neither are your ways my ways, saith the LORD. For as the heavens are higher than the earth, so are my ways higher than your ways, and my thoughts than your thoughts." (Isaiah 55:8-9 KJV)
So our reasoning as to why God decides to do anything, unless He tells us in His word, is pure speculation. But bear in mind the phrase in that last sentence, "unless He tells us in His word". And he does tell us a number of things, sometimes subtly, that gives us reason to believe.
It was God's will to create everything in the universe, including humans and the following verse at least explains it a little...perhaps not to our satisfaction, but at least it is an answer:
"Thou art worthy, O Lord, to receive glory and honour and power: for thou hast created all things, and for thy pleasure they are and were created." (Revelation 4:11 KJV)
If one stops to consider this, God was not under pressure by anything, to create all things. It had to be that He wanted to do it and He did it for His honor and glory. Does that not make sense? Why else would He have done so? And this quote is from the 24 elders John witnessed in his vision. A heavenly host. So they knew. And there are other scriptures that will reinforce that one. Here is one that specifies a reason for his creating man:
"According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love:" (Ephesians 1:4 KJV)
Be sure that you remember this last quote. It is more meaningful than is immediately obvious. God is glorified through the obedience of His Son and also His obedient Children. Our efforts to strictly obey God glorifies Him. Consider this passage:
"If any man speak, let him speak as the oracles of God; if any man minister, let him do it as of the ability which God giveth: that God in all things may be glorified through Jesus Christ, to whom be praise and dominion for ever and ever. Amen." (1 Peter 4:11 KJV)
These scriptures give us plenty of evidence that God created man to honor, obey and worship Him. But there is more behind it than just His pleasure, and that is the reason man was granted free moral agency. We can obey or disobey...our choice. But, there is reward if we obey and punishment if we disobey. That is to be expected. Children are expected to obey their parents (unfortunately that is a disappearing factor). Domesticated animals are trained and expected to obey their masters. We are God's creation and we are expected to obey Him.
Then comes the question, "Why would God create humans when He knew they would sin? Why would He not make them without an inclination to sin?" The answer is simple and is already expressed in the above information. It would not glorify God for a 'robot' to go through the motions of obedience. He loves man and He desires the love and respect from man. Free moral agency is the only way God can be assured that man does feel awesome respect for His infinite wisdom and power. And, in fact, if one does not, he cannot truly believe that God is real. Listed below this article are links to three others regarding the omnipotence of God, the omniscience of God and the omnipresence of God. I urge all to read those carefully and thoughtfully. If you follow those reasonings you cannot help but be awe stricken. And assuredly, on the day that Jesus returns and every eye shall see him, the awe will be overwhelming to those who have not believed.
"I love those who love me, And those who seek me diligently will find me." (Proverbs 8:17 KJV)
"The Lord is not slack concerning his promise, as some men count slackness; but is longsuffering to us-ward, not willing that any should perish, but that all should come to repentance." (2 Peter 3:9 KJV)
God not only created the universe and mankind, He planned everything out. He went the extra mile by sending Jesus to suffer and die for our transgressions, so that we could even be forgiven for our sins, if only we would obey Him. He has nothing else to do. The plan is laid out for us. Eternal bliss, a reward worth the effort.