Pregnant women exposed to organic solvents at work have a slightly higher chance of having a baby with a heart defect, a study shows.
The risk applied to hairdressers, nail bar workers plus women working in factories that make these chemicals, US researchers found.
But experts say the real risk in absolute terms is still very small.
Another study in the same Occupational and Environmental Medicine journal shows a dad's job also has an impact.
For men, working as a photographer, a gardener or landscaper or a gas worker, among other occupations, appears to increase the odds of various birth abnormalities, according to the study of nearly 5,000 fathers.
Again, the researchers say exposure to chemicals in the workplace may be to blame, but this particular study did not look at this directly.
The research in expectant mothers looked at organic solvents which are used for dissolving or dispersing substances and are found in paints, varnishes, adhesives and dyes.
The 5,000 women were asked to say what job they had been doing during their pregnancy and in the few months leading up to it to gauge what exposure they may have had.
When the researchers looked at the pregnancy outcomes, they found the risk of newborn heart defects was up to twice as high among the women who said they had been exposed to the chemicals at work.
The study authors, led by Dr Suzanne Gilboa of the Centers for Disease Control and Prevention in at Atlanta, say exposure around the time of conception and during the first 12 weeks of pregnancy - the first trimester - appears to pose a potential risk.
But experts stress the findings only suggest a link - they are not proof that the chemicals are the cause.
And the overall risk for an individual is small.
Prof Donald Peebles, a consultant obstetrician and spokesman for the Royal College of Obstetricians and Gynaecologists, said: "It's a fairly small increased risk of a rare complication of pregnancy. In the UK, around 1% of babies are born with these problems and what we are talking about is a small percentage of these.
"No one would say based on these findings that someone should give up their job.
"But it may be sensible to limit exposure when possible."
Amy Thompson of the British Heart Foundation said: "These results do not prove that solvents caused these congenital heart defects. Further research is needed to see if these observations are correct.
"If you have any concerns about your pregnancy or you are planning a baby and would like more information, speak to your GP or midwife."