From 6 months old you may feel comfortable about your baby riding in either a rear seat or (with support) in a cycle trailer. Both would be against some of the mainstream advice; the argument against is that the baby is too small to put a helmet on properly, and their neck muscles are too weak to hold their heads up for long and withstand the road shocks. The age at which babies are thought to be safe enough sitting up in a seat/trailer tends to be 15-18 months, depending on which manufacturer's/safety campaigner's/health professional's website you're reading.
If you decide to put your baby in a bike seat before 18 months anyway, make sure it is solidly made and attached to your bike, and claims to meet relevant safety standards. The best quality seats are heavy but recline so that the child can have a comfortable sleep on longer rides. These cost a lot more than the cheapest seats, though. You may want to add extra safety straps to make sure your child is secure. If possible, get a seat that has a small 'hump' in the front of the seat (between the child's legs). This is better than relying on a strap between the legs to prevent the child from slipping downwards.
When transporting a baby in a trailer, best to wait until they are at least 8 months old (can sit well unaided). They may need padding or a booster cushion to support them in staying sat up before the age of 12 months.
If you decide to put your baby in a bike seat before 18 months anyway, make sure it is solidly made and attached to your bike, and claims to meet relevant safety standards. The best quality seats are heavy but recline so that the child can have a comfortable sleep on longer rides. These cost a lot more than the cheapest seats, though. You may want to add extra safety straps to make sure your child is secure. If possible, get a seat that has a small 'hump' in the front of the seat (between the child's legs). This is better than relying on a strap between the legs to prevent the child from slipping downwards.
When transporting a baby in a trailer, best to wait until they are at least 8 months old (can sit well unaided). They may need padding or a booster cushion to support them in staying sat up before the age of 12 months.
