In The Apple Doesn't Fall Far From The Alibi, Frank and Ingrid go out with her taking him to a clinic. She reveals that she wanted him to fertilize her stored eggs so she could have children. Frank agrees wholeheartedly at the chance of being a father again. However, he learns that because of his habits and medications that his sperm count is low, with the chances being severely low for him to reproduce. Frank takes a sample cup home for him to deposit in but plans to have one of his sons do it. With Lip out, Frank goes to Carl and bribes him with the hundred dollars Ingrid gave him. Carl fills the cup all the way, unaware of what Frank intends to do with it. Frank uses Carl's sperm to impregnate Ingrid.
During BOOOOOOOOOOOONE!, Frank and Ingrid are at the lab and the doctor reveals their possibility of having a child are now up. However, Frank learns because of Carl's sperm, he and Ingrid are expecting septuplets and when the doctor reveals the risks of carrying the children to full term, he readily agrees to abort some of the kids. Ingrid is less than upcoming with this, but he seemingly convinces her. At the Alibi, he reveals the good news but is worried when Ingrid refuses to abort three of her kids and make him get a job to support them. Frank and Ingrid reveal this to the Gallagher children, who are shocked by this but doubt he could support more kids since he didn't do it with them.
During Los Diablos, Frank applies for the hobo loco to provide for his new family after hearing the cash reward.
In The Hobo Games, Ingrid starts to have doubts about Frank's capabilities, especially when her ex-husband Randy and the doctor implore her to change her perspective. Ingrid's worries are elevated by Debbie and the other Gallagher kids and she decides to test Frank but he fails. In the end, Ingrid leaves him while telling him that she will reduce the embryos. Her ex-husband also pays Frank off and he allows this.
Ingrid went through with her decision to reduce the embryos and gave birth to twins. Ingrid subsequently had an episode and abandon her kids and ex-husband while on a cruise and swam to shore.
In Sparky, Frank is about to leave the Gallagher House before Randy arrives with the babies to tell him that Ingrid left him and asks he takes the babies back. Seeing this, Frank runs away but is caught and talks with Randy who tells him about Ingrid's departure. The two argue for a while until Frank reveals that the babies born from Ingrid are actually his son Carl's children, something the arriving Carl overhears. Understandably, Carl was very upset with his father for using his sperm to impregnate the woman while Kelly argues with Randy on not leaving the kids with Frank or Carl. This argument was witnessed by their cousin Franny and Anne's family, who were amused by the drama. Frank looks at the children and realizes potential for them, deciding to take one. Although Randy protests this, Frank uses his superior manipulations to talk him down, as Carl realizes Frank's goal and wants to take part in the scam Frank has planned while telling Kelly that Frank is a master with scamming. Holding his new children, Carl decides to test them for their worthiness.
During Adios Gringos, Frank and Liam decide to sell the remaining baby to potential parents. However, they also take advantage of the people's desire for a baby by treating themselves with the money. Frank then takes the time to bond with his grandson and starts to care for the infant. His softness is noticed by Liam berates him for not staying focus but understands why Frank is doing so. Frank soon has second thoughts about selling the baby but the baby is taken anyway.
- They are unnamed as of yet and their genders haven't been revealed.
- One of the twins is revealed to be a boy, since Frank called him his grandson.
- They never met their cousins Chuckie Slott and Freddie Gallagher.
- Ironically, Freddie was upstairs while they were there.
- They never met their aunts: Sammi, Debbie, and Fiona.
- They never met their uncles Lip and Ian.
- They never met their paternal grandmother Monica.
- The way they were abandoned by their mother is similar to how their father was abandoned by their grandmother.
- Coincidentally, their mother and grandmother were bipolar.
- Similar to their cousins, Frank became excited to be a grandfather to them.
- In Season 11, when his partner asked Carl if he had any kids, Carl simply replied that he was 19. This indicates he's ignoring the illegitimate children, he already has.
- Near the end of Season 11, Carl seemingly impregnated a woman named Tish, possibly giving the babies a half-sibling.
- They make a cameo in the Hall of Shame.