Some people say the way women in ROTE always seem to end up as mothers is misogynist, and I don't wholly disagree. However, I think that is really reductive.
The idea that having children will complete a woman is a sexist one, if you only apply that to women. But in ROTE, we see that the men, especially Fitz, are as preoccupied with children as the women.
I see parallels in Patience and Verity, for example. They desperately want to conceive a child, not just for the sake of having children, but to have an heir and secure the throne. Both Patience and Verity almost blame themselves, Patience for her fertility issue, Verity for his virility issues. Having children is not an isolated choice, it's deeply political.
One of the main factors that distinguishes the world of ROTE from ours is that having sex and having children are inextricably linked. It's established that, unlike our modern world, there is no safe, reliable, and ethical method of birth control. Starling almost dies having an abortion. Molly makes herself ill to avoid conceiving. The only reliable method is a wizardwood charm (which I would have to make a whole post about the implications of that). But for most women in ROTE, the only method of birth control is abstinence. And of course, that doesn't always work. So for the women of ROTE, the choice isn't between having sex or having children, because everytime they have sex they are taking on the risk.
That's laid out very explicitly in the RWC with Thymara. She chooses to remain celibate, because in that context, it would be incredibly dangerous for her to get pregnant. She lambasts the men around her who don't see the risk women take one during copulation. This is a repeated theme we see with Molly and Fitz. He just sees the love they have, and doesn't recognize that by choosing to be together, he is harming her health.
This specific narrative choice of women always becoming mothers is a consequence of the worldbuilding. But it is also depicted with a lot of variety. Some women feel diminished by motherhood. Some feel completed by it. But motherhood is shown to be a unique privilege of ROTE's cisgender women.
One of the most interesting moments that defines Fitz's character isn't talked about often. It's during the Pale Woman's seduction. With Skill and drugs, she tries to manipulate him. She reaches into his soul and pulls out his deepest desires. She offers him power, and he is unmoved. She offers him knowledge, and he still is unswayed. But she identifies his one true desire, his biological and philosophical imperative. He wants a baby.
If women as mothers is one side of the coin, the other side is men as absent fathers. By choice, coercion, or circumstance, many of the prominent men are unable to raise their own children. Chivalry, Verity, Fitz, Chade, Burrich, Beloved. It's tragic and deliberate, and I would argue it's queer.
Some of the most famous works of queer literature are preoccupied with the unique ability of cisgender women to bring forth life, and the ability of heterosexual couples to combine themselves to create a child. Despite all our scientific advances, there is still no way to do that for a same-sex couple. ROTE has many foster parent-child relationships, and they're often very fulfilling. But they're often also bittersweet.
I truly think that this motif is to show a kind of profound yearning for children in a conventional family. Consider the fact that the absent fathers of ROTE all have elements of queerness, breaking the rules of social conduct. Chivalry had a bastard, as did Fitz and Chade. Verity used his nephew's body to conceive a child he claimed. Fitz and Chade are both assassins. Burrich and Fitz are both Witted. And Beloved is trans/gnc. Breaking these social rules incurs punishment. And the way they are punished is by not being able to raise their children.
And so I think the most likely conclusion of all this is that Robin Hobb might just really like kids and value the experience of having them. And I don't think that makes her an anti-feminist. She depicts many types of families and many types of mothers and fathers with complex characters and dynamics. To point at one shared motif, is, in my opinion, cherrypicking.
But I'm still developing my thoughts on this, so let me know if you have anything to add.
