Denis Leary had better keep an ear out for the angry clacking of Jenny McCarthy's high heels. Seems the comedian-cum-actor's new book, "Why We Suck: A Feel-Good Guide to Staying Fat, Loud, Lazy and Stupid," includes a chapter titled "Autism Schmautism," in which he appears to question -- in his usual restrained way -- the diagnosis of the brain development disorder.

"There is a huge boom in autism right now because inattentive mothers and competitive dads want an explanation for why their dumb-a-- kids can't compete academically," he writes in the tome (as excerpted by the New York Post), "so they throw money into the happy laps of shrinks to get back diagnoses that help explain away the deficiencies of their junior morons."

(Yeah, it's awful on a variety of levels, but keep in mind he does mockingly list himself as Dr. Denis Leary on the book's cover and is the same guy who penned a song titled "I'm an A--h---.")

"I don't give a [bleep] what these crackerjack whack jobs tell you -- yer kid is NOT autistic," he says. "He's just stupid. Or lazy. Or both."

Not surprisingly, the Autism Society of America takes issue with the "Rescue Me" star's conclusions, railing that "to suggest that families or doctors conspire to falsely diagnose autism is ridiculous . . . [His] remarks reflect the same misconceptions of autism being caused by bad or unemotional parenting that were held over 50 years ago, misconceptions that have been completely disproven by the scientific community."

But Leary insists his words have been taken out of context.

"The people who are criticizing the 'Autism Schmautism' chapter in my new book ... clearly have not read it," he said in a statement released Wednesday. "Or if they have, they missed the sections I thought made my feelings about autism very clear: that I not only support the current rational approaches to the diagnoses and treatment of real autism but have witnessed it firsthand while watching very dear old friends raise a functioning autistic child."

His point, and he does have one, is "not that autism doesn't exist -- it obviously does -- and I have nothing but admiration and respect for parents dealing with the issue, including the ones I know," explains the father of two. "The bulk of the chapter deals with grown men who are either self-diagnosing themselves with low-level offshoots of the disease or wishing they could as a way to explain their failed careers and troublesome progeny ... Please give me the benefit of the doubt by reading all of what I wrote before attacking me."

In a sit-down with the November issue of Vanity Fair, Leary says the autism chapter is his favorite in the book.

Jenny McCarthy and Jim Carrey, carrying her son Evan, rally in Washington, D.C., earlier this year to eliminate toxins from children's vaccines. (©Reuters)

When it's pointed out that unofficial celebrity autism spokeswoman McCarthy might picket his book tour, he responds, "Great. That would be really good for me. It will help sell more books."

Coincidentally, Jim Carrey's activist squeeze tops the cover of the latest Us Weekly, in which she poses with 6-year-old tyke Evan beneath the headline "Beating Autism: How I Saved My Son: Battling doctors, a failed marriage and her own guilt, Jenny McCarthy tells how her son Evan recovered from autism."

"When he finally hugged me," she dramatically shares, "I prayed, 'Please God, don't let this be the only time.'"

No word on whether Jenny is currently fashioning a protest sign to wave on Leary's book tour ...

Meanwhile, in other parenting news, even celebrity moms with unlimited resources worry about achieving just the right balance between their personal and professional lives.

"I'm in love with my life," Christina Aguilera tells People. "But Mama has to work, Mama has to do a job."

Christina hits the Africa Rising festival in London on Oct. 14. (©Retna Ltd.)

The peroxide-topped chanteuse, who donned her trademark work ensemble -- slathered-on war paint and a garish getup -- for the Africa Rising concert in London on Tuesday, believes 9-month-old Max will ultimately benefit from her career ambition.

"I think it's important to share what I love -- what makes me me -- with my son," she explains. "So, I change diapers and I breast-feed him and I play with him and then I work. I want to show Max everything about me."

As for her family expansion plans with husband Jordan Bratman, Christina enthuses, "Absolutely, we'll definitely have more kids," but she's light on details, like how many they want.

"I don't know," she sidesteps. "We'll play it by ear."

For now, Aguilera, 27, is happily showing off her post-pregnancy figure, which says she regained in the usual way: by working out and "trying to eat as healthy as possible. I'm a junk food queen."

And finally, Jessica Alba has no plans to leave 4-month-old Honor at home when she puts on her serious face to play a math teacher instructing troubled kids in "An Invisible Sign of My Own."

"To be honest with you, it's tough," she admits to People of spending time away from her tot, "and if it was any other movie, I wouldn't be doing it."

Still, the separation anxiety shouldn't be too bad.

"I love my daughter," adds the once-again super-slimline, bikini-cavorting actress, "and she's going to be with me every day on the set."