Thank you for your query.
As you know the sex of the child depends on the sperm.
If a Y bearing sperm fertilizes the ovum, a male child results, and if X bearing sperm does so, a girl child is conceived.
Hence, there is a 50 % chance of the child being of either sex.
if you are both reasonably healthy, you should not worry on any score.
please go in for a preconceptional counselling
as you are so anxious.
That would screen you and your wife for common conditions, infections, heritable diseases etc.
Ask her to take proper prenatal vitamins
Regarding your query on the blood group
Blood groups are inherited from our parents in the same way as other genetic traits (eg, eye colour). ABO
are the most well-known among the blood group systems.
Please go through the following link :
I hope that clarifies that part.