The former Girls Aloud star claims the 30-year-old 'X Factor' judge - who split from ex-boyfriend Tre Holloway last year - is ready to have kids, but for now they are both happy looking after their pet dogs.
Sarah, 32, told The Daily Mirror newspaper: ''I know that Cheryl is broody, but we both have our animals.
''Maybe I should think about having kids at my age, but i'm still young and while I do want them one day, right now I don't even think I'm responsible enough.
''I've got my dogs and I have my godchildren - three boys of three, six and nine. They are my baby fix for now. I will probably get more dogs and other animals before I have kids.''
Sarah - who lives in Buckinghamshire with her DJ boyfriend of 18 months Mark Foster - admits she doesn't want to ''leave it too late'' and will have kids by age 35, but is ''over the moon'' for her bandmates, Nadine Coyle, who welcomed a daughter with boyfriend Jason Bell in February and Kimberly Walsh, who is expecting a baby with partner Justin Scott.
Sarah gushed: ''Kimberley texted me a couple weeks ago and she is so excited. She is going to be a great mum, she and Nadine are so family orientated.''
The actress thinks it would be tough to recast her character, Winifred Sanderson.
Beck wishes he'd had ''more fun'' when Kanye West invaded the stage in protest at his 2015 Grammy Awards win.
The Duffer Brothers wanted to "experiment a little bit".