Hi mixue,
You cannot determine which zodiac sign is good for the baby based on both your birth signs alone.
Every year is a good year to give birth to. Some may say Tiger year not good coz Tiger very fierce and next time your child may be very fierce etc etc. There is no such thing. Trust me on this
The whole Bazi chart of the baby has to be taken into consideration. Bazi chart meaning the birthday and the time of birth. There is no way to determine if the baby is good for both of you or not before child birth unless you opt for caesarean birth, whereby Feng Shui masters will calculate for you what is the exact date and time to perform the caesarean birth so that the baby will come out, "owning" that particular Bazi chart.
"Owning" that particular Bazi chart means that the baby will have the character, luck cycle, marriage, wealth, career and health stated by the Bazi chart.
To give you a better idea, eg if your baby is a girl. For a girl, we tend to choose a Bazi chart whereby next time, she will have a good marriage with a loving husband. On top of this, we want her to have a good life too, so the luck cycle must be good, which means she will have good luck all her life.
In fact, the most important thing about caesarean date selection is that the baby cannot bring bad luck to the parents after he/she is born. This is the MOST important factor, on top of everything else.
So you can see, just using the animal sign alone is very superficial. The whole Bazi has to be taken into consideration.
I hope this clears some of your doubts