Your definition of "best possible" is brutally materialistic, and therefore, false as it applied to humans. The "best possible" mate for a woman is not the 6'4" Perfect Specimen with the Harvard Law degree--especially when said man is bringing no love to a marriage and creating a desolate spiritual wasteland for a wife to live in and a kid to grow up in. The best possible mate is one who is able *and willing* to pour out love on behalf of his wife and child, so that the home becomes a veritable garden under which all parties can bloom and flourish. *That* is healthy and successful as it pertains to the human being.
We got plenty of physically fit, smart kids out there who are thugs and gangsters precisely because every attention was given to their physical development and none to their spiritual. For the overall health of society, I'll take the decent, God-fearing, morally upright kid with a dozen disabilities and impaired intelligence over them anyday.
As for alleged "restrictions" imposed by Church and marriage, I will remind you that in the Church, we have something called courtship and the Holy Sacrament of Matrimony, complete with evaluations and interrogations of the couple being married to make certain they are emotionally and psychologically ready for what they are doing--and it is *precisely* to ensure that both parties are aware of what they are doing and choosing the best possible mate for themselves.
It is the secularists who fling themselves into marriage without any heed to what they are doing to themselves and their potential children--who marry degenerates and drug addicts.
I was simply pointing out how in the cold world of nature, prior to the positive constructs of society, the female would look for that mate which had the best physical and mental genes to pass on.
In pre-society days, strength and intelligence would help (not guarantee) insure survival of offspring.
You are correct that in today's society it takes more than that to insure children become productive successful people.
The restrictions placed on this process by society are there for good reasons.