Hilary Duff feels like ''Super Woman'' when she has to take care of her kids when they're sick.

The 'Younger' star is mother to seven-year-old son Luca Cruz and 15-month-old daughter Banks Violet, and has said keeping them healthy can sometimes a struggle, because they both seem determined to pass germs back and forth to one another.

She said: ''[I constantly have to] defend myself against them, because they're like Petri dishes.

''When Luca's going to school and coming home, I'm trying to teach him to not get all up in his sister's face right away. It's sad because he wants to just have his hands all over her and he's obsessed with her, which is so great. But I'm like, 'Just give her some space.' ''

Hilary - who has Luca with ex Mike Comrie, and Banks with husband Matthew Koma - will always pull Luca out of school when he's sick, and says making sure both her children are germ free can sometimes feel like a superhuman task.

Speaking in an interview with PureWow, she said: ''If my kid is sick, they're not going to class. Yes, if Luca is sick, it's hard for him to miss school, but I really believe that rest is so important. I'm like, 'Okay, you're going to nap and take it easy.' But the word 'nap' is like a four-letter word to a 7-year-old.

''Wrestling a little one to wipe her nose all day is a lot ... but those days are your badges of honour and make you feel like Super Woman when you're finished.''

Meanwhile, the 'Lizzie McGuire' star recently admitted she felt ''guilt'' about having a second child.

She confessed: ''The guilt that I felt for bringing her into the world was so big. It was just he [son Luca] and I for so long that he was like, 'Why? Why, Mom? Why would you do this? I really just love the way it is.' And it wasn't bratty, it was just so sad. I was like, 'How do I reverse this?! It's too late now.' It's such big feelings. When you're pregnant, everything just feels more magnified.''