Co-Applicants for child, world architects, rogue experiment

[DichotomousGal]

Set in the distant future? Society in the galaxy has eliminated almost all social ills of humans.. World Architects build societies.. often multiple people 4+ would apply to have/raise a child, thus assuring all emotional/financial needs of the child are met

It is discovered that a "rogue scientist/architect" created worlds without the aid of modern technology/controlled birth - these planets have conditions similar to medieval Earth's history..

Would love to remember the book's name.