Broader autism phenotype in parents of autistic children: reality or myth?

The team asked 40 parents of autistic kids and 40 parents of neurotypical kids to take two quick tests. One test measured how fast they looked at eyes in photos. The other test checked for autism-like traits with a short survey.

They also gave a block-design puzzle to see if either group showed the strong visual-spatial style often seen in autism. All tasks were done in one lab visit.

Only the fathers of autistic children were a hair slower to look at the eyes. The delay was tiny—about 40 ms—but it showed up every time. Mothers in both groups moved their eyes just as fast.

Survey scores and puzzle scores were the same across groups. So the broader autism phenotype, or BAP, showed up in one narrow spot: dads’ eye gaze speed.

McIntyre et al. (2002) saw a different eye problem in parents: they aimed their eyes less accurately on a memory-guided task. The 2008 study adds a second, independent eye marker—slower social orienting—suggesting dads may carry two subtle gaze quirks.

Demello et al. (1992) found that fathers of autistic kids cope well despite extra stress. Pair that with the new eye-delay data and you get a fuller picture: these dads adapt fine, yet show tiny social-attention differences you might miss in conversation.

O'Reilly et al. (2009) looked at another father trait—waist-hip ratio preference—and also found a difference. Taken together, the studies don’t contradict; they just map different BAP ‘hot spots’ that can coexist quietly in the same person.

When you coach families, don’t assume slow eye contact from dad means disinterest. It may be a harmless BAP trait, not resistance to training. Use clear verbal labels (“look at my eyes”) and extra wait time before prompting. This small tweak can cut misreads and keep fathers engaged in your parent-training sessions.