Child born through Sperm Transfer

Hi Friends

Please answer this....

Avinash and Latha are unable to bear child, so they consult a Doctor and it is found that Latha's sperms are weak.

The couple engages another lady by name Geetha who agrees to get the sperm of Avinash injected in her womb.

After 10 months the child is delivered and Geetha hands over the child to Avinash and Latha for a consideration amount of Rs.2 Lacs for having borne the child.

Now what if after some years Geetha claims the child as hers and demands a share in the property of Avinash.

Which LAW governs this type of cases.

Are there any case already decided by courts on this matter?

Please give me the links.