A survey of 1,000 members of the campaigning group Mumsnet showed that most rated the UK behind other countries such as Spain, Italy and Greece for general family friendliness.
More than four out of five said having children had made it harder to progress in their career and three out of four said they were less employable.
Almost nine out of 10 of those polled said flexible working was a priority, but 60% believed UK companies and services were not family friendly.
Justine Roberts, chief executive of Mumsnet, said: “Other countries seem to welcome families with open arms but in the UK parents often feel their children are seen as an annoyance.
“At Mumsnet we want to work with business and government to change this, and that’s what our Family Friendly campaign is all about.
“We want to see workplaces where parents don’t have to deny that their kids exist. We want firms to state on the door that employees don’t have to feel bad about asking to go to sports day.
“Being family friendly is good for business too. Companies shouldn’t spend time and money training staff only to see them walk out the door once they’ve had children because their workplaces don’t fit with family life.”