Modern issues close to Leto’s heart?
If I were to try to narrow down any pertinent issues I would probably say that the foremost that come to mind is anything dealing with personal autonomy. This would include issues of right choose, birth control access, and right to die. These are all issues pertinent to, and fringing, her domain as a independent chthonic mother goddess. As a goddess who is by her nature hidden and obscure, she is a goddess of high degree of privacy and self actualization and autonomy. It would make sense for her to have a hand in these things.
Of course some might think there is a contradiction between right to choose and goddess of mothers. But I say there is not because of her devoted bond to her children I would argue that she is more apt to favor motherhood for only those who desire children and wish to be mothers.
I would also say that she favors surrogate mothers who put themselves forward to bless children on loving parents otherwise unable to produce their own.