UK intelligence needs to do more to recruit middle-aged women and mothers to be spies, using websites like Mumsnet, according to senior MPs.
In a report, the Intelligence and Security Committee (ISC) said such women were an "untapped recruitment pool" for MI5, MI6 and GCHQ.
It said more than half of the civil service were women, but the figure was 37% in the intelligence agencies.
Hazel Blears, the Labour MP who led the report, called for a culture change.
Women make up 53% of all civil servant roles but the report found that in the three intelligence agencies there are "disproportionally more" female members of staff at junior grades, with only 19% reaching senior grades.
The report said women should not be limited to certain jobs.
Ms Blears said: "I personally want women to be attracted to a career in intelligence and to feel there is the prospect of real advancement."
Speaking to BBC's Woman's Hour she said things are improving but are still not good enough.
She said "We need to keep using women's skills and experience.
"If you have been running agents in Afghanistan, you are a really valuable resource.
"It is absolutely crucial that after you come back having had children that you don't go into something like HR or finance."
Ms Blears claimed there could be an issue for women with children when MI6 officers needed to travel abroad.
She said: "There is a bit of testosterone in the system that says 'tickets, money, passport - we all have to get there'.
"And if you've got children, finding 24-hour childcare is often very difficult.
"I feel quite strongly that the agencies can plan better, even for emergencies, you can have plans in place, you can have childcare providers."
Ms Blears said some female recruits at MI6 had complained about the attitudes they encountered within the service.
One female recruit told the committee that she thought the organisational culture was male dominated.
She said: "I was told once during training that I could have used my 'womanly charms' to build rapport by a role player, which I found very frustrating as I wondered what my male colleagues did to build rapport without such charms."
A government spokesman said it was determined to increase the number of women in the security and intelligence agencies, particularly at a senior level.
He said: "The agencies have made good progress, which is acknowledged by the ISC, and clearly demonstrated by the representation of agency boards and by the increasing availability of operational roles with flexible working patterns.
"We are committed to ensuring the most talented people succeed and reach top positions, regardless of gender, ethnicity, sexuality or disability, and will report to the ISC by 2016."
Former US Secretary of State Madeleine Albright praised Ms Blears' three-year investigation and said it echoed work she had done at the CIA.
She said: "Diversity should be pursued - not just on legal or ethical grounds - but because it will result in a better response to the range of threats that threaten national security."
Mumsnet chief executive Justine Roberts offered a tongue-in-cheek response to the suggestion that the parenting forum was a suitable place to recruit female spies.
Referring to Cold War spy tactics, she said: "I'm afraid I'm unable to comment as I have an urgent appointment with a rock in St. James's Park."