'Sister Wives' : Robyn Brown Tells Kody She's Sometimes 'Baby Hungry' as He Contemplates Adoption

Sister Wives' Kody Brown and his wife Robyn aren't ruling out the possibility of welcoming more children into their family.

On the latest episode of the hit TLC series, the couple had a heart-to-heart discussion, during which Robyn and Kody shared their thoughts about potentially adding another child to their brood.

With his four plural wives — Robyn, Christine, Janelle and Meri — Kody has a combined 18 children ranging in ages from 26 to 4 years old. Kody's youngest child is 4-year-old daughter Ariella, whom he shares with Robyn. The couple is also parents to young son Solomon and Robyn's three eldest children — Dayton, Aurora and Breanna — from her first marriage.

While sitting outside of her Flagstaff, Arizona, home, Robyn, 42, recalled a previous conversation she had with Kody, 52, about having more kids.

"You know how like, a couple years ago when we went back to Vegas for, a little like, trip and I said, 'Are we done having kids?' We both kind of went, 'Ehh. I think no, I think we're done,'" she said to Kody.

"And you keep making comments and jokes and then it's, 'I don't know if I'm done,'" she said to her husband, who asked with a smile if she was "calling" him "out sort of."

"A little, yeah," Robyn said with a laugh. "I brought you out here to say: What is going on?"

Taking into account her own "biological clock," Robyn wanted to be on the same page as Kody.

"I'm 41 years old. We need to decide this and now. Like, there's a biological clock ticking. I'm not getting younger. We can't sit here and stall out on this if this is what we're going to do," she said in a confessional.

"I have days when I'm baby hungry and I really want another baby," she admitted.

Furthermore, she said she "100 percent" wanted "to have Kody's commitment because he is older, he's got wives that are like, completely done. And if we're going to have a baby, we're both going to be committed and you're going to be holding a baby," Robyn told cameras.

Hearing his wife pose the question of where they were at, Kody said he was "caught in a conundrum, completely."

"You know, this is what I've always done, this is what I've always been. I've always been fathering and having special experiences with little people 'cause they're just sweet," he told Robyn.

"I'm pretty sure that I've been having kids for 26 years. There's this real joy about having a little one," Kody said to cameras.

But while raising young daughter Ariella has been "just a wonderful experience," Kody wasn't sure if he was ready for more. "But at the same time, I'm caught in this conflict because Ari's been weened for a year and she's still keeping us up at night," he explained to Robyn.

"It started to get better once she was weened and stuff," Robyn said to Kody, who disagreed. "No, it's not better," he told her.

"It's mental exhaustion," Kody said to cameras. "You're arguing with a 4-year-old who has the words of a 10-year-old and the logic of an idiot."

While Kody seemed as though he was leaning towards being done having kids, Robyn didn't feel "done."

"Women talk about that feeling of like, 'Oh, I'm done.' I've never really got that," Robyn explained to her husband.

Though she's never had an exact number in her mind, Robyn wanted however many children she's meant to have.

"You know when you're young and you're just thinking about having children and people will say, 'How many kids are you going to have?' I would always say, 'Just as many as I'm supposed to have. As many as I've made promises to,'" Robyn said to cameras.

Becoming emotional, she continued, "It is, it's a big deal to me. To make sure, to make sure all my babies are here with me. That's all," she added, beginning to cry. "In my head, I made promises to a certain amount of children to be their mother. You know, in the pre-life and I want to fulfill all those promises."

As for Kody, he wanted to make sure his relationship with Robyn wasn't solely centered on their children.

"I want to have a life with you that's not just all about our kids," he said, before asking her opinion. "What do you think about that, though? Do you feel like, hallelujah?"

Robyn felt a mixture of emotions. "I feel relieved and sad at the same time," she confessed.

"I believe that we exist in a spiritual form before we are born and come to earth. I believe that I have had interactions with some of my children, you know when they were a spirit ... before they were born," she told viewers, further disclosing the "crazy fear in my head that I'll leave somebody behind."

Realizing his wife was "mixed" on where she stood, Kody told cameras he felt he was "walking on eggshells here in a way because I don't want to discourage Robyn from us having a baby if she feels a premonition that we should."

The mother of five then went on to share about the vision she had of a little boy. "I don't know what it was, but I had something, someone hanging around for a long time," she told Kody. "Just a little dark-haired boy."

Hearing that wasn't helpful to Kody. "You have not helped me answer this question," he said to his wife, who laughed.

"I felt like the decision's made and then she blows me out of the water with a visual of a dark-haired boy," he said in a confessional, later adding, "My blonde hair really comes out in the kids, so I doubt that we'd have a dark-haired boy. Maybe we're supposed to adopt, I have no idea."

While adoption wasn't something he previously considered, Kody was more open to the idea for the future.

"Adoption was never an option because we were having our own children. But now that we're winding up here, the idea of adoption is something that would be more appealing to me," he told audiences.

Ultimately, the pair didn't come to a conclusive answer.

"Well, if you don't feel done, maybe we need to think about this some more," Robyn said to him. "If I don't know that I'm done, maybe we need to make sure."

"I don't know what else to do with it," she said to audiences, "because I don't have a strong answer either way."

Sister Wives airs Sundays (10 p.m. ET) on TLC.