(Partnering may or may not include marriage or reproduction, and depending on your succession laws, can be a same-gendered Sim).
You may only have one “Primary Spouse” per generation, but may move in any number of secondary spouses.
Since the traits of the parents have an influence on the traits of their children, you can try to engineer children by selecting spouses with desirable traits, but this is no guarantee.
You are allowed to use fruit and/or music to influence the gender of an unborn child, should you choose to do so.
With the addition of alien babies can also be brought into the family via abduction.
They are mainly here to keep the challenge balanced and maintain a degree of difficulty as you play through your 10 generations.There have been many reports that the automatic generation of random townies peters out over time, leaving the dating pool barren.To combat this I am easing up on the restriction of using gallery sims for Legacy Challenge spouse material.The restriction on the number of Sims moving into the Legacy family house has been lifted.You may now move in as many sims as you wish, as long as none of them brings in any money.
On the gallery, look up #Legacy Loves (name suggested by Boss Jinja) any and all families you find there can be brought into your world and become eligible spouses. Simply make one or more sims in CAS, then upload them to the gallery wiht the #Legacy Loves tag.