A Tory MP and grandson of Sir Winston Churchill has raised recruitment concerns, warning that "touchy-feely political correctness has absolutely no role whatever in the British Army".
Sir Nicholas Soames, MP for Mid Sussex, said he accepted that the Army "must do what it thinks it needs to get people to join", but added:
"I think they ought to be extremely cautious about the message they send outside."
He also said it was a "matter of the first importance" that the system "must not be altered in such a way that it will produce only pale imitations of what is actually required".
Tory Leo Docherty, a former British Army captain who led the debate on the size and strength of the UK's Armed Forces, also said the Treasury should know there is a "very large cohort of MPs who are absolutely determined" to ensure the Ministry of Defence (MoD) is "properly resourced".
For the government, Defence Minister Mark Lancaster insisted Defence Secretary Gavin Williamson had made a "strong case" for why there needs to be greater investment - with negotiations continuing.
Former defence minister Sir Nicholas described the British Army as "probably the best fighting force in the world", with soldiers likely to cite their discipline and training as the key to their confidence.
He said: "It's, therefore, a matter of the first importance that the system that produces the young men and women of this calibre must not be altered in such a way that it will produce only pale imitations of what is actually required.
"So far the Army has held this line but only just.
"It's a constant battle for all three services to fight off politically correct notions which are, rightly, an anathema to the ethos of the Armed Forces."
Sir Nicholas added: "Whilst I'm all for the Army, if it really feels it has to, adapting its recruiting to some vaguely woolly notions, it is important that we continue to get the outstanding young men and women who we are so lucky to have in our Armed Forces and that the training does indeed prepare them for what might come."
The MoD, he said, made a "huge mistake when it let the contract for recruiting to Capita, who've made a real pig's ear of it".
He went on: "I don't mean to sound like a stick-in-the-mud but touchy-feely political correctness has absolutely no role whatever in the British Army....
"I accept that the Army must do what it thinks it needs to get people to join, but I think they ought to be extremely cautious about the message they send outside."
Mr Docherty (Aldershot) told the same debate: "The prospect of any form of capability cuts, I think we will all agree in this chamber, are entirely untenable and we should resist them."
He added: "It is our duty to make it very clear indeed to the Treasury that there is a very large cohort of MPs who are absolutely determined to ensure that the MoD has a sound financial settlement and is properly resourced."
Replying to the debate, Mr Lancaster said: "I think it was Stalin who said that quantity has a quality all of its own - and I think it's a very reasonable point.
"The worth of an armed force is ultimately determined by what it can do."
"This means the military power it can bring to bear, the readiness with which it can respond and the effects it can achieve in the different circumstances it may be asked to achieve them."
Mr Lancaster, asked if the new defence review would have to be fiscally neutral, replied:
"No, that's not what I'm saying at all, and I think, to be fair to (Mr Williamson), my boss, he has made a strong case as to why there needs to be greater investment in defence and that negotiation will continue."
Theresa May, speaking at Prime Minister's Questions, told MPs:
"We want to ensure that the defence budget is being spent intelligently and efficiently, and that we're investing in the capabilities we need to keep our nation safe."