Table 3 Challenges in manipulation of the placental phenotype

• Targeted delivery of vector to the placenta: promoter and receptor-based approaches

• Implementation of gene knock-down technology

• Regulated expression would be of significant utility

• Useful approaches will include minimally invasive monitoring of transgene expression during pregnancy

• Improvement in vector application (replacement vs. insertion)

• Alignment of enthusiasm with reality of resource availability = prioritization of research goals