But an alarming increase in attacks against children across Japan in the past year has raised fears that her son and daughter could become victims, or even killers themselves.
"They are five years old and two now ... but we hear about such terrible incidents involving children who are not much older than them," Mutsuko, who asked to be identified only by her first name, said.
"I can't think they would ever do anything like that, but I am sure the parents of the children involved in these crimes thought the same."
Six months after an 11-year-old girl killed a 12-year-old classmate with a paper cutter, almost severing her head, Japanese society is still pondering how such a terrible thing could have happened in a country that has long instilled a sense of community and respect for others in its children.
The attack on Satomi Mitarai was not a one-off incident.
In 2003, 212 children under 14
were detained for serious crimes
A junior high school girl pushed a five-year-old boy off the top of an apartment building in Tokyo in June - the boy landed in bushes and survived.
A girl, 15, was arrested the following month in the northern prefecture of Toyama after stabbing a stranger. The girl said she did it to get attention.
In 2003, 212 children under 14 were taken into custody for serious crimes, a 47.2% increase on the previous 12-month period, including 93 in connection with murders.
Although statistics show that Japan remains safer than most countries in the world, the brutality of the crimes is shaking Japan's faith in its young people.
"It is very alarming to see this level of violence in children, and I feel it has a lot to do with the parents," Noriko Hama, a professor at Kyoto's Doshisha University, said.
"At home, they stick the TV on or give them a computer game to play with and they just become disassociated from the real world."
New fears for the safety of Japan's children were recently raised with the news that a 22-year-old, who committed a murder when he was 14, is to be freed in January.
In 1997, the man, whose identity was not released, was 14 when he killed Jun Hase, 11, cut off his head and propped it against the gates of his school. He later murdered a girl riding her bicycle and, in letters to the media, taunted police by saying they were too stupid to catch him.
Having busy, working parents is
affecting children's social skills
Japanese parents aren't prepared to cope with such violence. "Their parents cocooned them so that they are not able to deal with stress," Hama said.
A Tokyo psychologist, Chie Okuda, remembers when life was different. "When I was a schoolgirl, I used to come home and later go out into the fields with my friends and neighbours to play, and my parents never worried at all," she said.
According to Okuda, "When parents are busy and working, they don't have time to talk with their children and the kids don't get to mingle with others, so their social skills suffer."
"Society really needs to start helping itself by looking after those that are most at risk, and that's the children"
Doshisha University, Kyoto
There is concern that as more mothers have to work, the traditional Japanese nuclear family is likely to further come apart.
"I think there is a growing awareness of the problem in government circles and a lot of hand-wringing but, if anything, policy and political thinking are making things worse," Hama said.
The wave of juvenile crime has exasperated the government. Yoshitada Konoike, a junior minister, said the parents of a 12-year-old boy who killed a four-year-old by throwing him off the top of a multi-storey car park in Nagasaki in July 2004 "should be dragged around town and beheaded".
Doshisha University's Hama says society needs to focus more on children.
"They say the answer is more discipline in schools. Teachers are being criticised for failing to spot problems before they get out of hand and the emphasis is not being put on the parents to deal with the problem, as it should," he said.
"We have to reach the conclusion that society really needs to start helping itself by looking after those that are most at risk, and that's the children."