The link could explain the significant decline in the male-to-female sex ratio seen in birth registries over the past few decades, say the researchers.
Passive smoking also appears to have a detrimental affect.
Among 8,960 singleton births between 1998 and 2003, the male-to-female ratio was lowest at 0.67 when both parents smoked during the pregnancy. A male-to-female ratio of 1.21 was observed if there was no smoke exposure in pregnancy.
Presenting the findings at a meeting of the Royal College of Paediatrics and Child Health last week in York, the researchers said sperm carrying the Y chromosome may be especially susceptible to the effects of cigarette toxins.
Study lead Professor Bernard Brabin, from Liverpool School of Tropical Medicine, said: ‘This is a massive public health problem.’