The Look Who's Talking actor - who is the mother of two adopted children - has reacted to new guidelines from the Academy of Breastfeeding Medicine, which recently urged the use of "gender-inclusive language" such as "chestfeeding," "parent's milk" and "human milk feeding".
Alley, 70, wrote on Twitter: "BREAST-FEEDING IS what WOMEN do. Women also bottle feed. Men bottle feed too. We do not have to buckle to the insanity of the minuscule minority of lunatics who make us feel guilty for not sharing their insanity. “Chest feeding?” “human milk feeding?” WTF STOP IT!!!"
The Cheers star went on: "I’m a little tired of the degrading and nullifying of women and their abilities. Breastfeeding is one of our abilities. It’s a beautiful and important ability. Knock off the nullifying of women fir the sake of lunatics. Equal rights does not equal insanity."
Defending her comments Alley added: "We all have opinions. Probably the main reason social media is so popular. Especially on our own sites. I guess it’s also inviting other opinions of our opinions but I don’t feel obligated to be “sweet” when people are nasty to me about my own site opinions. BlAh blAh blAh.
"It’s our personal responsibility to agree or disagree with concepts. My only point here today is don’t let insanity force you to pretend like you agree with the insanity. It’s part of the insanity to shame you into agreement.
Read more: Kirstie Alley criticises PC culture
"My views of this BS are not political. I have plenty of friends from both political persuasions who SHARE the view of the INSANITIES being shoved down our throats by pervs trying to degrade our society. Don’t be afraid to disagree with people who seek to pervert workable morals."
Alley is often outspoken on social media - and in 2020 publicly voiced her support for Donal Trump during the US presidential elections.
She recently said she felts she had been "blackballed" by Hollywood as a result.
Alley told Fox News show Tucker Carlson Today: "People go, ‘You’re so brave.’ I go, ‘No, I think I’m stupid’. Because honestly, it is a real situation. And it is a real blackballing situation. It’s so strange to me because artists are free-thinkers, for the most part.
“You can be cooking meth and sleeping with hookers, as long as apparently you didn’t vote for Trump. I feel like I’m in The Twilight Zone a bit, with the whole concept of it."
Watch: Kirstie Alley feels 'blackballed' by Hollywood after voicing support for Trump