Have you tried seeing a gynae? There are gynaes who offer fertility assessments and consultations to help couples pinpoint the reasons why they are finding it difficult to conceive. I can recommend my gynae. His name is Dr Chris Ng. His clinic is at Orchard Blvd. He offers fertility screening...
Have you tried seeing an ENT specialist for your son's coughs? Some chronic coughs may involve problems in the ENT areas. It could even be allergies or rhinitis. You can try Dr Lau Chee Chong at Mt Elizabeth. He's good with kids and may be able to help.