Short version of an answer.... NO ONE KNOWS!!
I get asked where clubbed feet comes from all the time... and based on what I can tell - your answer depends on what your doctors opinion is on where they come from. But from speaking with other parents of clubbed feet babies... I think the real answer is that there is no way to know what caused it.
Clubbed Feet, also known as or congenital talipes equinovarus (CTEV), is a common birth defect effecting approximately 1 in 1000 live births. The root cause for clubbed feet comes from a long list of possibilities, and it could be one or many from the list. The list of possibilities has been broken down into two categories; Postural or Structural. Without treatment, persons afflicted often appear to walk on their ankles, or on the sides of their feet. Approximately 50% of cases of clubfoot are bilateral (both feet). This occurs in males more often than in females by a ratio of 2:1.
Structural TEV is caused by genetic factors such as Edwards syndrome, a genetic defect with three copies of chromosome 18. Growth arrests at roughly 9 weeks and compartment syndrome of the affected limb are also causes of Structural TEV. Genetic influences increase dramatically with family history.
Postural TEV could be caused by external influences in the final trimester such as intrauterine compression from oligohydramnios (deficiency of amnio fluid) or from amniotic band syndrome (ABS). However, this is countered by findings that TEV does not occur more frequently than usual when the intrauterine space is restricted. Breech presentation is also another known cause.
So, there ya have it... some basic information but no real answers. Obviously it's easy to think in my case that we are dealing with Structural TEV because my husband used Ponseti braces to fix his being pigeon-toed (feet turned inward) as an infant/toddler and now we've produced two children with clubbed feet. All things considered, it is still very rare to end up with two children affected - so we should certainly go out and buy a lottery ticket!