There is no role in my life that I value more than being a mother to my five children. No career has ever brought the same fulfillment, and very little in the way of "work" achievements has brought the happiness to my heart that I have felt from giving my children a chance at the best life I can. Learning new things does give me great satisfaction, but I don't feel complete until I share that new knowledge with people who might benefit from it--in my case, that is usually my family, although I use this blog to try to reach a wider audience. I know that my idea of "a best life" differs from that of many others, just as people and cultures differ, but it appears to me that a universal characteristic of good parents is that they want "the best" for their children.
A core part of the Abrahamic religions is God's promise that Abraham would have more descendants than there are grains of dust on the planet: "And I will make thy seed as the dust of the earth: so that if a man can number the dust of the earth, then shall thy seed also be numbered" (Genesis 13:16). Someone actually estimated the numbers of grains of sand on Earth and came up with "roughly (and we're speaking very roughly here) 7.5 x 10^18 grains of sand, or seven quintillion, five hundred quadrillion grains" (https://www.npr.org/sections/krulwich/2012/09/17/161096233/which-is-greater-the-number-of-sand-grains-on-earth-or-stars-in-the-sky). That's a lot of descendants. One estimate of the number of people that have lived on the earth so far in its history is 1.08 x 10^11. That is one sixty-nine-millionth of 7.5 x 10^18, and a lot of the people who have lived on earth do not have ancestry known to be from around the land of Canaan, which means that they aren't literal descendants of Abraham.
Joseph Smith, founder of the Church of Jesus Christ of Latter-day Saints, taught that through Christ, all who are faithful disciples of Christ have the opportunity to have "eternal increase," that is, lots of descendants. That is part of the Abrahamic covenant. But it's not enough to just have a lot of children. God wants us to be good to those children.
I have some recent examples in my family history of people who brought children into their family only to ignore, mistreat, and outright exploit some of them. I have no easy answers for this. It's not the number of children a person has that determines whether they'll be unkind to their offspring, for large families can be loving and happy and small families can have severe issues. Of course, I want to help fix any biological dysfunction that might be behind those issues.
One such biological issue is the impaired "theory of mind" often seen in pyschological disorders and brain damage. When a person doesn't see others as separate entities with their own equally-important thoughts and feelings, it's only natural to end up exploiting others to meet one's own wants and needs. Commandments and laws--assuming they're prosocial ones--can help keep those exploitative tendencies in check and promote more mutually-beneficial behaviors, but they are not as good a solution as would be improvements in theory of mind because they are ineffectual without transmission and acceptance of those commandments and laws.
Another biological issue that interferes with good parenting is the inherent tendency towards efficiency in the human brain. Addiction is a natural process of the brain's being "efficient" about obtaining short-term happiness but simultaneously obstructing the development of alternative neural pathways that could also bring happiness. Many young children are neglected and mistreated due to parental addictions, so I would like to see effective treatments for addiction become widespread. Unfortunately, many people are currently making large amounts of money off various addictions, so I don't know whether it will be possible to overcome the influence of those who have no qualms about hurting others to promote their own interests.
