I dont even know if i spelt the title right

Have you ever seen this? My friend introduced it to me a year ago. She had most of the series on DVD and we watched them wwhenever she came over. It is like in Rosswell Mexico when an alien ship lands, three ''kids''(see??? quotes!) come out and two get separated from the other. They are all adopted, the two stay as brother and sister, but the other kid....yeah he by himself. I didnt see the whole thing but i think it is on the Sci Fi channel.